[pron]

Except, as you say, all those factors always exist, so we can compare things against each other. No language to date has grown its market share by a factor of ten at such an advanced age [1]. Despite all the hurdles, successful languages have succeeded faster. Of course, it's possible that Rust will somehow manage to grow a lot, yet significantly slower than all other languages, but there's no reason to expect that as the likely outcome. Yes, it certainly has significant adoption, but that adoption is significantly lower than all languages that ended up where C++ is or higher.

[1]: In a competitive field, with selection pressure, the speed at which technologies spread is related to their relative advantage, and while slow growth is possible, it's rare because competitive alternatives tend to come up.

[tialaramex]

This sounds like you're just repeating the same claim again. It reminds me a little bit of https://xkcd.com/1122/

We get it, if you squint hard at the numbers you can imagine you're seeing a pattern, and if you're wrong well, just squint harder and a new pattern emerges, it's fool proof.

[pron]

Observing a pattern with a causal explanation - in an environment with selective pressure things spread at a rate proportional to their relative competitive advantage (or relative "fitness") - is nothing at all like retroactively finding arbitrary and unexplained correlations. It's more along the lines of "no candidate has won the US presidential election with an approval of under 30% a month before the election". Of course, even that could still happen, but the causal relationship is clear enough so even though a candidate with 30% in the polls a month before the election could win, you'd hardly say that's the safer bet.

[tialaramex]

You're basically just re-stating my point. You mistakenly believe the pattern you've seen is predictive and so you've invented an explanation for why that pattern reflects some underlying truth, and that's what pundits do for these presidential patterns too. You can already watch Harry Enten on TV explaining that out-of-cycle races could somehow be predictive for 2026. Are they? Not really but eh, there's 24 hours per day to fill and people would like some of it not to be about Trump causing havoc for no good reason.

Notice that your pattern offers zero examples and yet has multiple entirely arbitrary requirements, much like one of those "No President has been re-elected with double digit unemployment" predictions. Why double digits? It is arbitrary, and likewise for your "about a decade" prediction, your explanation doesn't somehow justify ten years rather than five or twenty.

[pron]

> You mistakenly believe the pattern you've seen is predictive

Why mistakenly? I think you're confusing the possibility of breaking a causal trend with the likelihood of doing that. Something is predictive even if it doesn't have a 100% success rate. It just needs to have a higher chance than other predictions. I'm not claiming Rust has a zero chance of achieving C++'s (diminished) popularity, just that it has a less than 50% chance. Not that it can't happen, just that it's not looking like the best bet given available information.

> Notice that your pattern offers zero examples

The "pattern" includes all examples. Name one programming language in the history of software that's grown its market share by a factor of ten after the age of 10-13. Rust is now older than Java was when JDK 6 came out and almost the same age Python was when Python 3 came out (and Python is the most notable example of a late bloomer that we have). Its design began when Java was younger than Rust is now. Look at how Fortran, C, C++, and Go were doing at that age. What you need to explain isn't why it's possible for Rust to achieve the same popularity as C++, but why it is more likely than not that its trend will be different from that of any other programming language in history.

> Why double digits? It is arbitrary, and likewise for your "about a decade" prediction

The precise number is arbitrary, but the rule is that the rate of adoption of any technology (or anything in a field with selective pressure) spreads at a rate proportional to its competitive advantage. You can ignore the numbers altogether, but the general rule about the rate of adoption of a technology or any ability that offers a competitive advantage in a competitive environment remains. The rate of Rust's adoption is lower than that of Fortran, Cobol, C, C++, VB, Java, Python, Ruby, C#, PHP, and Go and is more-or-less similar to that of Ada. You don't need numbers, just comparisons. Are the causal theory and historical precedent 100% accurate for any future technology? Probably not, as we're talking statistics, but at this point, it is the bet that this is the most likely outcome that a particular technology would buck the trend that needs justification.

I certainly accept that the possibility of Rust achieving the same popularity that C++ has today exists, but I'm looking for the justification that that is the most likely outcome. Yes, some places are adopting Rust, but the number of those saying nah (among C++ shops) is higher than that of all programming languages that have ever become very popular. The point isn't that bucking a trend with a causal explanation is impossible. Of course it's possible. The question is whether it is more or less likely than not breaking the causal trend.

[tialaramex]

Your hypothetical "factor of ten" market share growth requirement means it's literally impossible for all the big players to achieve this since they presumably have more than 10% market share and such a "factor of ten" increase would mean they somehow had more than the entire market. When declaring success for a model because it predicted that a literally impossible thing wouldn't happen I'd suggest that model is actually worthless. We all knew that literally impossible things don't happen, confirming that doesn't validate the model.

Lets take your Fortran "example". What market share did Fortran have, according to you, in say 1959? How did you measure this? How about in 1965? Clearly you're confident, unlike Fortran's programmers, users and standards committee, that it was all over by 1966. Which is weird (after all that's when Fortran 66 comes into the picture), but I guess once I see how you calculate these outputs it'll make sense right?

[pron]

> means it's literally impossible for all the big players to achieve this

Only because they've achieved that 10% in their first decade or so, but what I said is the case for all languages, big and small alike (and Rust doesn't have this problem because it needs a 10x boost to approach C++'s current market share, which is already well below its peak). But the precise numbers don't matter. You can use 5x and it would still be true for most languages. The point is that languages - indeed, all technologies, especially in a competitive market - reach or approach their peak market share relatively quickly.

You make it sound like a novel or strange theory, but it's rather obvious when you look at the history. And the reason is that if a technology offers a big competitive advantage, it's adopted relatively quickly as people don't want to fall behind the competition. And while a small competitive advantage could hypothetically translate to steady, slow growth, what happens is that over that time, new alternatives show up and the language loses the novelty advantage without ever having gained a big-player advantage.

That's why, as much as I like, say, Clojure (and I like it a lot), I don't expect to see much future growth.

> Clearly you're confident, unlike Fortran's programmers

Yes, because I have the benefit of hindsight. Also, note that I'm not saying anything about decline (which happens both quickly and slowly), only that technologies in a competitive market reach or approach their peak share quickly. Fortran clearly became the dominant language for its domain in under a decade.

But anyway, if you think that steady slow growth is a likelier or more common scenario than fast growth - fine. I just think that thesis is very hard to support.