"Are you actually IO bound? I seriously doubt it."
Most apps and games could open instantly, unless you are doing something like heavy map generation or hitting the network. But it would require structuring the app specifically for it and there is often no incentive to do so.
Tiny files are fine if you fetch them from NVMe and keep the queues fed, i.e. you need to issue multiple concurrent reads, not do it sequentially. Not being on windows helps too.
Business logic is quite a bit more likely to just be waiting on IO, usually fetching from the DB or sending/receiving over the network. This is because there's a lot of business logic where those things are _everything it does_.
In a world with 400 Gb/s NICs, being IO bound takes some doing. How much SW manages that without SIMD, even on multiple cores?
depends on what you call I/O. From the perspective of the caller, that’s the entire stack starting at a http library call or sql driver call. If those can’t use the hardware to their fullest (or can’t, the way you’re using them) your process becomes I/O bound from its perspective.
Amen. CPU have stopped improving significantly a decade ago or more. IO never stopped.