Python has become a hugely critical language for science, AI/ML, finance, etc. and the current state of tooling has lagged the language's importance. I can think of lots of ways a company that solves that problem could add adjacent products and monetize them. Enterprise support, tooling for building and deploying custom lint rules, supply-chain security, managed builds, etc.

> X is not strong enough to build a company from.

I mean, these are the famous last words of a lot of non-visionaries. I'm not saying that Ruff is some kind of unicorn, but there are a lot of cases where a seemingly small improvement on an existing technology resulted in a very successful enterprise. Docker, for example. There are others that I'm sure people will chime in with.