If typescript itself defines a format, it's hard to imagine that the majority of people won't switch to it.

Though while there's a lot of type-data tools, are there actually a lot of type-data formats out there right now? I've been using zod, and it doesn't have one. You have to use code to tell it about a type. Someone did make a library to let zod load types from pure data, but the format used there is... typescript source code.