yes, but they do that sometimes.

back in the days when I was in CVG and they were running the late night ORD-CVG on mainline, with the return the early morning flight, I was delayed a couple of times leaving CVG in the morning due to late inbounds the night before - the schedule adjusted somewhat but it was often pretty close to the minimum rest time. There was another time when I was on the late night outbound from ORD and had a deadheading crew as fellow pax so they could staff the next mornings flight on time.