SVG is much better at vector art use cases. Flash was horrible from user pov (constant os and browser compatibility problems, unending stream of weekly "ads can pwn your computer" level security holes, proprietary black box nature, ate your battery, hard to procedurally generate, didn't integrate with the web and dom, etc etc).
All true, but there’s such a massive library of content for Flash that they must have done _something_ right. Maybe it was just luck, maybe timing, but it’s amazing to me that so many games and videos are caught in this particular technical dead end. My understanding is that HTML5 just never offered the same primitives for content creation, but I’m unsure why there was no economic incentive to create them.
Adobe Flash/Animate provided a best-in-class animation and vector art package that still has little competition. Animate can actually export to HTML5, but they didn't bother using the SVG/SMIL animation model. Instead, they pre-render everything as a series of spritesheets and render them to a canvas.
I can see why they did this - the SVG and canvas vector rendering models are different enough to make blindly rendering SWF content to it cause rendering artifacts. (It's one of our biggest longstanding bugs in Ruffle - canvas masks just look weird.) However, Adobe could have ameliorated this either in the exporter, the authoring environment, or by pushing for Flash-style mask options in web standards that deal with vector rendering. Instead, they went with the far worse but quicker option of prerendering so they could say "hey we totally do HTML5 now".
