And yet prior to FAR 117 (widely criticized here) NINE hour layovers were quite common... reduceable to eight, for the flying crew! Yep, part 121 was all a bed of roses. I was actually shocked the first time I flew one of those as it truly did approach the unsafe realm.

117 got many things wrong, but the hard work 10 hour min layover, not reduceable, is one thing that they got right.