On both Aloha 243 and United 811, it was the first-class cabin that broke apart. In both cases seatbelts kept passengers from being sucked out of their seats. Aloha 243 lost a flight attendant who wasn't buckled in... but United 811 lost two whole rows of first class seats, passengers and all. And at least one passenger was sucked into the engine. So maybe being behind the engine isn't so bad.

It's a common trope that the rear of the aircraft is safer, since it usually crashes nose-first. Back when the rear rows were the designated smoking section, one would always hear a few rounds of "smoking saved my life!" after a fatal plane crash.

They charge more for the convenience of getting seated and getting off, and by the precise amount that people will pay for that. Nothing more.