[mgkimsal]

You nailed it.

Company X chooses... ocaml, in this case. Someone taking a job there either needs to know it already, or have a 'willingness to learn'. OK - I'm willing to learn it, but at what expense? I dig in to ocaml for a few years, get really good at it, and find, say, 4 years from now, that the market for ocaml developers is really bad. I've gambled and lost, even if it "paid off" for the company.

Most developers are making rather rational choices, regardless of what tech company founders would like to think.

I do run in to people who are ".net or die" and "java for everything", and they'll never ever consider bothering to learn a new tech stack. And... they chose wisely enough that they may not have to over the next 10-15 years - almost anything you'll want or need to do for a large majority of computing/development needs will probably have .net/java equivalents (whether they're the best implementations or not is irrelevant to these people). But... choosing Haskell as a sole focus... they may end up having to uproot a family to move to another location to get another equivalent Haskell job in a few years, which most people don't want to have to do.