Cool, Steven Wittens is behind this. The header at https://acko.net/ is one of the first examples of WebGL I remember seeing in the wild, and still one of the cleanest. Looking forward to seeing where this goes!
The still strikes me as one of the very few useful usages of WebGL that exists even today. There's other usages of course, like figma, sketchup, etc... But those rarely (if ever) benefit from the web's primary advantages of ephemeral & linkability, and would work perfectly fine as just classic desktop apps. Kinda like an awful lot of tools in those spaces still are.
Majority usage of webgl still seems to otherwise be ads & shopping. It seems likely that webgpu is going to be much of the same, although it has a chance of graduating out of the web platform as a potentially useful middleware abstraction for native apps that want to use the GPU.
Adobe Flash Professional still exists as Adobe Animate: https://www.adobe.com/products/animate.html
Useful for exporting movie and packaging assets / animations to then be consumed by a custom engine but not worth the effort that much when you have spine, etc. which are better supported and used in the industry.
Scaleform still seems to be used by some AAA studio (I'm always surprised to see it) but I can't imagine it they will continue to use it for long.
Also, you can add support for notifications, and for the developer there are more options for monetization.
If you are only targeting the web, you're better off with a game engine specific to the web.