Having the project maintaining its own compiler infrastructure is a separate issue from having it the same package as the base system. The latter is just that, a packaging issue. At least to me, installing a system without the compiler makes sense in many cases. Not only reduced disk space, but also less binaries and thus a smaller attack surface for local privilege escalation and other nastiness.
I compile everything so I can learn how pkgsrc works. I hope to be able to contribute as a maintainer some day.
And that is exactly why I argue that compiler-onboard as an ethos is seriously missing in todays OS world, where the OS and the toolchain have been (arbitrarily) separated for nefarious reasons.
(relaxed)-ahhhh
/me takes a swig of coffee...
/me compiles all....
G