Apple specifically refused to support Flash in mobile Safari and the original sandbox model for apps prevented any kind of perfomant virtual machine for something as sophisticated as SWF (or Java or .NET). That's improved some in the 15 years since, although the sandbox is still fairly conservative and tight.
But at the time, I don't believe Adobe engineeing publically bothered to swim upstream against this, and while there were third-party attempts to run SWF files or AIR applications on iOS they were indeed janky and slow (as you would expect).
The current sandbox model for apps still does not allow any sort of performant VM; by design. Hell, one of the biggest announcements of Apple's DMA compliance is just that they had to provide entitlements to access some kind of JIT support on iOS. They are extremely pissed that they had to do that, only they are supposed to be allowed to JIT code.
That being said the only people who complain about not having JIT on iOS are Mozilla and people who want to run game console emulators, which Apple doesn't want their users having because they despise the Church-Turing thesis. Game developers that use engines with VMs in them just develop around the execution of those VMs being very slow.
Apple wasn't refusing to support Flash on mobile Safari. The actual story is more complicated: Apple tried to collaborate with Adobe four times on mobile Flash but, depending on who you ask, Adobe either shipped code that just plain didn't work on phones, or Apple couldn't be bothered to even get Flash to compile. Probably both are true. The very public open letter from Jobs regarding Flash is after Adobe said "fuck it" and decided to ship what they had as a packaging solution for developing iOS apps. While most of the open letter is written to say "this is why we're not shipping Flash as a browser plug-in", the real reason it was published was to justify rule changes in their developer agreement intended to prohibit porting Flash apps to iOS.
Said rule changes were overturned in 3 months, thanks Obama.
But at the time, I don't believe Adobe engineeing publically bothered to swim upstream against this, and while there were third-party attempts to run SWF files or AIR applications on iOS they were indeed janky and slow (as you would expect).
So I'd give your memory like a B+ on this one!