Actually, this is up to Nintendo and Sony, not Apple...

And, speaking from experience, Nintendo definitely wouldn't be on board. As far as I'm aware, they have never authorized any kind of third-party emulation of their games; even their first-party emulators like the NES Mini or Virtual Console have always been limited-time offerings with relatively small selections of games.

Getting the game ROMs is definitely illegal. But they can’t have any say in the actual emulation and emulation software.

Good luck having apple to approve a game where to do anything you have to google things, the game cannot tell you how to google and any public popular resources telling how to do it getting struck with DMCA.

They can approve the emulators though, which they don’t currently.

Could it be because emulators need JIT and JIT is a window to jailbreak?

JIT doesn’t necessarily mean a window to jailbreak - you can still have efficient sandboxes.

It doesn't but IIRC most jailbreak methods on current devices (iPhone, PlayStation, Switch etc) were due to JIT. On PlayStation, it required escaping freebsd jail as well?

Getting ROMs is legal in a lot of circumstances, either by backuping the game yourself or if you own the game but download a ROM (like https://law.stackexchange.com/a/41876)

Sure! As I said I was fantasizing, maybe I should have qualified this a bit more :)