Your assertion that there aren't great benefits to TS, based on an article I didn't read, is spoken like someone who has never worked on an enterprise project in TS that has _good_ types. Note, I wrote an article called "Why Typescript Won't Save Your Project", so I certainly have been there. Just today, one of my PRs triggered a build failure because TS picked up there was an epic (Redux Observables) using an action whose primary audience was a different epic, and whose payload had changed type. Had it not picked that up, we would for sure have had runtime errors.

I also upgraded a library recently that was not written in TS, but had TS types, where the only way I knew what properties were invalid in the new version was the TS errors.

Also, as other people have pointed out, the end of ActionScript 3 isn't at all mysterious. It was murdered by Steve Jobs.