I remember trying out Macromedia Flash 6.0. My GUI apps were ugly at the time. Learning to build something like I saw in the movies could take years. Then, Flash let me throw together beautiful, animated interfaces like it was nothing. One could do quite a bit after one tutorial.
(Note: Quick shoutout to Dreamweaver 6.0 which was a power, WYSIWYG editor. Today, things like Pinegrow might fill the niche.)
It's death as a hugely-popular tool was largely due to Apple and Adobe. SaaS model isn't helping it far as wide adoption goes. It also got popular through piracy which hints the replacement should be profitable and widely deployed like open source.
I think this might be a good opportunity for a license like PolyForm Non-Commercial. Free users either can't commercialize their content or, like CompCert Compiler, must make the outputs GPL'd (or AGPL'd). The Flash replacement would have a fair, one-time price for unrestricted use with source or you share like they shared with you. What do you all think?
The "pay to sell your work" model is basically what Autodesk does to provide a version of Fusion that's free/accessible to the hobby 3d printing market while still protecting their b2b revenue.
I haven't looked in a while, but I believe there's music and audio production tools with similar approaches.
Of the two, I think Adobe is most responsible for the decline of Flash. Even if smartphones had never entered the picture, laptops (where efficiency is important) were quickly becoming the most common form of PC, which would've eventually made Flash as it existed under Adobe untenable as well. The timeline was just accelerated by smartphones.
Honestly I can't understand the mental calculus that went on in the heads of Adobe execs at the time. Yes, cleaning up the ball of mud that the Flash codebase had become and making it not so battery hungry wouldn't have been an easy task, but it would've futureproofed it significantly. Instead they decided to keep tacking on new features which ended up being entirely the wrong decision.
EDIT: The constant stream of zero-days certainly didn't help things either. A rewrite would've been worthwhile if only to get a handle on that.