Some of you might remember when a 3mb flash animation could pack in some 5 minutes of animation, with the more advanced ones even having chapter/scene selectors, which could also include clickable easter eggs and other kinds of interactions during the scenes.
They actually did, Flash is still around (now called Animate), and can export to a HTML+JS bundle you can include on your own website.
Problem is nobody uses their own websites these days, and you can’t upload stuff like that to Twitter/Facebook/YouTube.
There were lots of programs for making Flash content though, and there was a lot of knowledge about how to make stuff in it. There isn’t the same culture of remixing stuff now. More interactive web games are also more server dependent even for elements where they don’t need to be, unlike tons of old standalone flash games