I know that they do that a lot in high-frequency trading and in the gaming industry. Both of them are not an option to me. Of course, this is done in academia, but that's not "really" an industry.

I suspect there is a lot of real world simulation, especially of some physics (and graphics, but that is less interesting to me), where such optimizations are needed. But as far as I understand, in general such help is not really appreciated there. The cost of to other programmers to deal with necessary changes existing code, as well as the fact that hardware and compute time are cheaper than programmers, seems to make things difficult. I seriously consider learning to write python interfaces to do "magic" to python projects, but I don't know whether there actually is a market for that.

What are your experiences? Is anybody here paid to speed things up?

Edit: Typos