> There is no free equivalent available targeting HTML/JS
I commented to the same effect elsewhere, but I would take this a step farther. There is no alternative, free or paid, Open Source or proprietary, targeting any platform (even just iOS or Windows) that is as good as Flash was at rapid prototyping and accessible game creation.
To me, the focus on the web is really frustrating. Unity is not as good as Flash was for rapid prototyping. Gamemaker is not as good as Flash was for animation. It's not the platform's problem that literally no one has found a way to merge animation, artwork, and programming in the same way as Flash did.
It's not that there's something awful about the web and that it ruined the ability to make that tool. Literally no one for any platform for any motivation has ever replicated Flash even just as a content creation tool.
So why are we talking about the web at this point? WebGL, Canvas, and WASM are powerful enough to replace Flash. That is not the issue anymore. I think when people touted the web as a replacement for Flash, there was an expectation that some company or Open Source initiative somewhere was going to make effective tools and that never happened. And instead of talking about the fact that the entire games industry has been unable to replicate Flash, we're attacking the Open web instead.
I agree that Flash was prematurely killed online, I agree that HTML advocates were too dismissive about the problems. But we are far past that point. The web kept its end of the bargain, the APIs exist, but nobody else built the necessary tools. We should be talking game engines right now, not the web.