Typescript was still 0.x "public preview" and I was knee deep in a codebase that was a massive amount of jQuery scattered across mostly inline script blocks in a huge number of ASP.NET templates many of which were "components" subcluded by other templates (meaning who knows how many final inline DOM-blocking script blocks per final output page). I had helped invest a ton of effort into an AMD infrastructure to start to modularize all those inline script blocks, but the conversion was pretty slow going (AMD modules were a pain to write by hand) even though the clear performance win of it helped keep it a clear priority project. Typescript even in 0.x made all of that so much better and easier if for no other reason that it made writing and managing AMDs so much simpler (and type checking helped code quality so much as bonus).

A lot of compile time tooling didn't fall out of the sky because they were solutions looking for problems. They solved real problems at the time. It's amazing to think how few developers today remember "the bad jQuery days" and "server-side template inline script block hell" and AMDs (good riddance, though they too solved important problems in their time). I don't think they can understand how much "our compile times are slow" is a better problem to have. I'm not sure if I envy some of them having missed some of the worst of those past problems.