Scala does not use semver. The last major release was 2.13.0, not 2.0.0. That's a bit confusing I guess.
What that means is, they haven't just added some features, they redesigned/rewrote to language from ground up to simplify it and make formally sound. I actually don't know any other language that does that (though I'm sure there are others, maybe Haskell is one of them).
In addition, a lot of features are very impactful and unprecedented, such as match types. To me, for a mainstream language (even though a smaller one), it certainly feels fast pasted.