At our (national) university (not in the US, but similar living cost), a tenured professor shortly before
retirement has a salary of about $80'000. Assistant professors get ~$40K. (To be fair: profs at private
universities get about twice as much). I don't know about other departments, but at least in engineering,
both tenured and assistant profs put in a lot of hours.
If you're working in the systems area (low-level stuff such as OSes, compilers, etc), it's hard to write
even two papers per year and grad student, because we actually implement our ideas, debug them,
and may not be able to publish if the results are worse than expected. And most projects are too big
for one student, so a whole team is working on it.
In computer science, we compete with everyone who has has interet access and a computer. The guys
at, for example, Tsinghua University in Beijing work extremely hard and are at least as talented as your average
grad student in the US or Europe. If we publish something new, a framework, a new scheduling algorithm,
etc., for that first paper we do have some slack. Once it's out, anyone is free to improve the ideas there
and publish a follow-up paper. From that moment on, even though we have a good head start, it's either
publish fast or work on something entirely new. Unfortunately, not everybody has a new cool idea every day.