that is I've not read a post from anyone who possesses such powers
At present I'm no longer in such a position, but for more than a decade I did possess such powers, and the reason I visit here is primarily to listen and learn. It will come very handy if I ever get called to such high office again.
The issue is far-far more complex, and no, in many cases the airline would not make its dough. The issue evolves around overnight flights with a sector length of 4-4.5 hours, and is linked to night curfews, daily aircraft utilization and crew requirements per aircraft.
For airlines with night curfews at home base, the only way to use the aircraft during this time is to send them out late in the evening and get them home by the time the curfew is lifted. The commercial realities are that these night flights are not only unpopular with crew, but - surprise, surprise - also with passengers, translating into low yields. As a result the maths work out only if the rotation can be completed by a single set of crew, but not if one whole set of crew needs to be stationed permanently at the destination (it is not just the hotel cost, but one full extra set of crew is needed for the aircraft).
The alternative is of course to drop the destination, keep the aircraft grounded at base during the curfew, and operate the aircraft with two less sets of crew (which is what European low-costs typically do, as they do not need connecting passengers to fill half the flight, hence they can afford orphan sectors in the mornings and evenings). But this means that the ownership cost of the aircraft needs to be spread over fewer revenue flights, pushing their cost up. In many cases, without the night flightpair to spread costs (and the 8 hours flight time is a lot), the whole daytime operation may become unprofitable.
No easy answers, and am not advocating anything, just trying to show that the picture is a bit more complex than simply limiting two sector night shifts to 9 hours across the board (and why 9, why not eight or 9:30... ?)