[skybrian]

It's kind of irrelevant since it's a different team with a different software niche and design aesthetic, but since you ask:

Dart struggled for years to find a killer app, though Flutter now seems to be a good bet.

Originally the idea was to replace JavaScript and everyone except TypeScript pretty much failed at that. (I mean failed from a popularity point of view, they often succeeded technically.)

I'll also point out that coming from Google is kind of a mixed blessing these days, from a popularity standpoint.

[ChrisSD]

It should be noted that TypeScript succeed by augmenting Javascript, instead of strictly replacing it as most other languages tried to do.