You're referring to the mid-late 2000s. I'm talking about the early 2000s. You can hate Flash all you want, but for all the HTML5 hype we had back then, there isn't a single authoring tool today that's not even equivalent to the original Flash Studio (by Macromedia). It was the only tool in internet's entire history where both artists and programmers could work on together. Or sometimes even without each other.

What do you have now with all your fancy React and JS libraries that's pulled off something that Flash did?

Flash died because of the carcinogen that Adobe is. It could have been the future of HTML5 had they actually invested in it.

Look at the pathetic state of HTML5 today. What tool should a non-coder use to output something you could do with keyframes on Flash studio in 5 minutes in the 2000s? There's absolutely nothing quite the equivalent of Flash. You need to write 100+ lines of code to get something decent out of HTML5 that involves animation. There are paid niche tools, but nothing at the scale of what Flash pulled off.