But see, I don't want it. Then, one day, I do, because I'm working on something a bit different (or on the same thing, just with a different approach).
All those libraries buy me the freedom to do a bunch of different things. That freedom has some value, even if I never use it.
Having stuff in the standard library sounds like the definition of a feature -- well, actually multiple features.
Plus, it's not like those are loaded into memory when not used.
Lastly, there are several stripped down java vms, some are even used for real time / embedded work.