Not to sound overly critical, but is it just me or does this come off as a somewhat selfish point of view? My father was a tenured professor and growing up I heard enough horror stories from his department to know that a career as a professor at a research university is no easy career. But at the same time, isn't a major part of your job instructing students? I understand the importance of grants, conducting research…
Wait... you're assuming the alternative to the practice suggested in the OP is spending a lot of time focusing on instruction? (Of _undergrads_?)
I think you are misunderstanding the 'typical' approach to tenure-track career. I can assure you that the majority of people doing the "80 hour" work weeks are not focusing on teaching.
While the OP didn't mention really mention teaching, I would honestly assume the the author spends as much or more time on instruction/teaching, and does as good or better by her students, than the 'typical' workaholic junior tenure track faculty. The workaholics are not spending spending 80 hours a week because they're spending a lot of time on teaching, I assure you.