Just because CMU does it too doesn't mean that it's reasonable. Students who are stressed out and sleep-deprived aren't going to be learning effectively - there's lots of research that indicates that sleep is necessary for forming long-term memories.[1] Better to split the course into two semesters.
You've touched on an important point. Namely, that bootcamps actually can't very feasibly split or extend their curriculum. It's not a coincidence that most of these schools offer 10-12 week sessions. Moving past that and the logistics of relocation, tuition, expenses & health care become much more difficult to manage.
[1] https://en.wikipedia.org/wiki/Sleep_and_Memory