This isn't true, you're looking at Flash as a monolith when really it was a bunch of things.
To it's users it was a place many teenagers learned how to be creative with computers, building games and animations and expressing themselves in online communities which had more in common with a proto-youtube/tiktok than what you think of online web games today.
Worth pointing out Adobe didn't care about that part of Flash in the slightest and almost all their dev work post-Macromedia was building systems that community couldn't really understand or see a need to use.
What Adobe saw it as was a video player and a cross platform application tool, but to be honest it just seemed like the team in charge of the cross platform frameworks were just not talented enough to make something at all performant, air/flex UIs always just felt incredibly janky and slow, the Mac team as well just never bothered optimizing Flash on a Mac until Jobs kicked off then suddenly it ran close to Windows speed 2 months later after running literally 30%-60% Windows speed for years.
Jobs was definitely right to kill the latter of what I'm describing but unfortunately the former was collateral damage.
Apple’s App Store is filled with ugly apps that have poor performance. People will write that kind of software on anything that has enough programmability.
So it’s not that Jobs killed Flash to save users from bad taste. It was because Flash was the most widely deployed cross-platform runtime of the desktop web era (at one time on 96% of computers!) and he didn’t want Adobe or anyone else to have that kind of power anymore.
At that point it wasn't as much about control[0] but as that the runtime really was bad. I used it when they released Flash on Android and it was completely unusable. Extremely laggy, the mouse events did not map to touch events well at all, and it would out of memory crash all the time.
Replacing flash on the web with HTML5 was actually a good thing. It's just unfortunate that nobody has built any good web authoring tools for "mere mortals" to use.
[0]Remember the iPhone was launched with no App Store, and Steve Jobs just thought that everyone should write PWAs in HTML5. It took developers jailbreaking the phone, making native apps, and massive internal pressure from Apple people to make him go ahead with the store. But it was partially about control because at the time Flash was a huge source of security bugs and drive-by virus infections from just loading a flash ad. Apple would have to release emergency OS updates if they had bundled flash and they never wanted to be tied to someone else's schedule.
True, Jobs did not want Adobe to have that kind of power, but I am also glad he killed it, Flash apps were fugly, heavy, and the runtime created security problems.
But the main reason, I think, was the flash runtime was an energy hog, and at the time (up until iPhone 4 or so), that meant using a Flash website on an iPhone would shorten battery life and put the blame on Apple.
At the time, they vetoed many things for that reason.
The results were fantastic, actually. The Flash era was a great time, and lots of important and influential software came out of it.
The problem Steve Jobs had was that Flash was too resource/power hungry to run on the first iPhone, so his decision to disallow it was a defensive one.
Interestingly, you could make iPhone apps with Adobe Air (a descendent of Flash) and such apps still run today! So there have more longevity and compatibility than apps written with the official Apple tools. Pickle's Book is one such app you might like to try out.
Today's iPhones are capable of running Flash much better, and iOS is now a resource (CPU/RAM/battery) hog all by itself. So what was really achieved in the long run?