I really miss Macromedia Flash. There wasn't a single tech like Flash and SWF format which flourished with so many indie games and animated movies available without any extra downloads (other than Flash Player). Barier to entry was so low.
Now, take SVG, it has potential to do everything what SWF could. But there is no editor like Flash and scene/object based coding solution like ActionScript. And each browser has own quirks so only simple SVG is guaranteed to be displayed everywhere.
Well it still exists as Adobe Animate which can export to html.
Comparing SVG to Flash seems like an apples to oranges comparison anyway. The format does not have to do everything that Flash did but can rely on the other technologies in the browser.
Adobe Animate is a sad shell of Flash. It only supports 2D, where its ancient predecessor supported 3D 20 years ago. It is a largely dead product, although parts of the Flash spirit lives on in After Effects, which is a video-centric tool.
I think web assembly can be comparable, e.g. unity/unreal/godot can compile to the browser pretty easily.
The problem is that each of these apps can be quite bloated and in the tens of MBs range not the usual single digit MB.