So your argument is that an ecosystem of external crates which are created and maintained mostly by individual contributors is on average better than the standard library backed and dogfooded by trillion dollar company and used by other giants of the industry? Can't say I agree.
Not to mention nothing prevents anyone from using or writing their own library only for the parts that need specialization. You're free to do that and many have.
And standard libraries can be versioned and deprecated too.
I actually wouldn’t be surprised, if only because the standard library is so much harder to make backwards-incompatible changes to. I would generally expect that the average quality of the third party libs is lower, but the top 1% is probably better than stdlib.
Eg I don’t find the stdlib logging library particularly great; not bad, but not impressive. Ditto for the stdlib errors package before they added error wrapping
Not to mention nothing prevents anyone from using or writing their own library only for the parts that need specialization. You're free to do that and many have.
And standard libraries can be versioned and deprecated too.