I think you may underestimate how approachable flash was to non devs. There is something about an animation engine that triggers code on a given frame that upends how most devs think about code. The main reason to keep it around is I’m not sure there’s anything else like it. Hypercard I understand was close.
That said, part of what made flash approachable was also the ecosystem and the world in general. I don’t expect to see another cambrian explosion that was flash again in my lifetime, and it’s probably ok to let it die, given how tied it was to the zeitgeist of the early 2000s. Still, working for a replacment platform rather than just exporting from existing platforms is probably something the world will likely always need every generation. It’s all about what catches the interest of kids, and there is a known dichotomy between building for experienced users and building for beginners. And platforms will tend toward experienced users over time (mosty because repeat customers are much more profitable than new customers).
Ya, it's not that we want to keep flash alive, it's that we want a similar approach to building web content. Unity has some similarities, but it's much more complex to do basic things.
Every popular game engine will export to HTML5/Webassembly now, there's really no need to keep Flash alive just for the sake of nostalgia.