I think there are quants who make a lot of money and then find that money isn't everything and who wants to do more public work afterwards. Nassim Taleb sort of fits into that model, even through of cause he doesn't count since he has an academic degree.

You need space and time to do good work, and people outside academia or places like Google labs just don't have either.

Einstein was in neither academia nor Google labs in 1905. He simply had a day job that left him and his wife enough time.

In the area of medicine I consider it possible that someone without an academic background has a startup idea that turns out to change medicine. Given that I studied bioinformatics there a bit of a change that I overestimate people who never went to university to look at certain paths of thoughts but I did spent years thinking about certain ideas outside of a formal academic setting.

But in STEM there is a rigorous footing for these things that helps a lot with not running off to lala land

I'm not sure whether the academic physics community community really succeeds at this task these days. The Gender Science community even less.

I think there are multiple different ways of getting feedback that keeps you from going of into lala land that are different from academia. In the field of health QS partly has the property. It's not perfect but neither is academia.

If a quant outsider constructs a very influential model, I could see that ending up in a Nobel, especially if it goes through a conventional publication process. I think though quants are generally kept very busy with non-academic things.

For finance in particular, my impression is that quants that make good discoveries keep them to themselves, because that's how they make money! After a while, some academic notices the same thing, formalizes it, and then publishes, and then the opportunity is gone.