This would require a very strong assumption that geniuses are a commodity. That all it takes is to be in the right place and be given the right opportunity and anyone could have done what he did.

It's probably true. Given enough time and people, someone's going to do it. You just gotta look at ancient civs and how they often would independently come up with really complex stuff. Given the spread of knowledge since that time, some discoveries might be easier.

Billions of people over hundreds of years produces lots of opportunities.

This was not OP's argument. The argument is that we could have replaced Feynman with whoever was second-best-yet-not-a-chauvinist-pig, and we would get exactly the same outcome, sans sexism.

That's one way of reading it, sure.

The iPhone wasn't invented by Apple, they just had a great combination of timing on manufacturing processes, great marketing and a decent UI to start with.

There is no doubt in my mind that we would've made the same progress with any other company, albeit perhaps cosmetic differences.

I think this is translatable to most other advancements. It's nearly always iterational, and either someone's first, different people discover something independently or it's a mashup of separate discoveries.

History makes geniuses, smart people exist everywhere.

With all due respect, I think scientific breakthroughs aren't really comparable to innovations in consumer goods

You can tell people that their behavior in one area is wrong without failing to respect their achievements in another area, so your statement (as well as manifestly being false; disrespecting Feynman doesn't magically create another equally-talented physicist) is a non-sequitur.

> their achievements would go to someone else

It doesn't work like that unfortunately.