There's also the cost that you are likely to just spin your wheels retreading old ground. Examples to the contrary are notable, but notable because they are rare.
I made this assumption for many years, and yes, that cost would be high. I eventually discovered that, more often than not, everyone assumed that someone must have already investigated a particular hypothesis but if you tried to identify that "someone" it turned out that they didn't actually exist. After doing this exhaustive search a few times in a few different domains and coming up empty handed, it changed my perspective on the matter, to my great benefit.
Searching for evidence that someone has actually done the work is relatively efficient. It never fails to astonish me the number of times that everyone believes a particular bit of ground has been thoroughly tread yet, if I try to find concrete evidence that someone has done the work, there is no evidence that anyone actually has. There is a strong cognitive bias (I don't know if it has a name) where everyone assumes that someone else has already tried every obvious or reasonable approach and that belief is treated as factual.
>if I try to find concrete evidence that someone has done the work, there is no evidence that anyone actually has
Unfortunately, the fact that negative results tend to get little if any publicity works against you here. And it's probably worse outside, not inside of academia. How often would a project team in some big company, or a couple of guys in a garage try out some promising alternative approach to something, fail to realize an advantage over the conventional approach, and then go out of their way to publicize that failure? That would be extra work for no - or even negative - gain.
It might just be meant to be humorous, but even "If at first you don't succeed, destroy all evidence you even tried" sounds more likely than "If at first you don't succeed, put some extra effort into telling everyone".
Would you be willing to give an example of an area where it was widely thought that "someone" had already checked all the obvious possibilities, but you were able to find an obvious possibility that actually hadn't been explored?
I think you're arguing for doing surveys of literature, which I would also argue for. My argument was against the veneration of From First Principles, which is largely incompatible with Maybe Someone Already Did That, More Completely, More Correctly, A Long Time Ago, And It's Easy To Check First.
This here is the real danger. Many people choose to reinvent the wheel and end up finding out that their approach was actually horribly flawed compared to what already existed, or they turned out not to have the resources to see it through. It takes a brilliant person with a lot of luck to make this work in an advantageous way.
Two great examples come to mind right away, both from Elon Musk. SpaceX was founded on first principles and now he's been able to undercut competitors by an order of magnitude. Conversely, his attempt approaching car manufacturing from first principles in the gigafactory has proven to be a complete disaster.
There are also the times when you discover a tech, a library, or a language that supposedly solves your issue, but in reality only goes 80% of the way.
Unfortunately, it can take a lot of work to then a) find workarounds (which in my experience tend to become a maintenance nightmare) b) try alternates (which may have other but similar limitations) c) pull out and start doing it yourself anyway.
Searching for evidence that someone has actually done the work is relatively efficient. It never fails to astonish me the number of times that everyone believes a particular bit of ground has been thoroughly tread yet, if I try to find concrete evidence that someone has done the work, there is no evidence that anyone actually has. There is a strong cognitive bias (I don't know if it has a name) where everyone assumes that someone else has already tried every obvious or reasonable approach and that belief is treated as factual.