True. A big appeal for me with TS is that the inference engine is decent, so doesn't feel too ceremonious, and I can also tap out of the type system at any point and write a bit more gnarly code. Typing just the boundaries can be super helpful sometimes.

If by "a couple" you mean 10 to 15, then yes, that's correct.

Look at the modern type systems we have around and try to see how they are different from what was mainstream by that time.

I am not talking about the state of type system. But, how they were projected as one. Especially when dynamic languages were getting popular.