Yea, I think it's cultural. Americans have been trained by FF programs for two decades that premium cabins are basically available to elites and anyone clever enough to talk their way in. There is just zero understanding for premium cabin integrity in the US. If you actually paid for domestic J or F, you were a moron. Delta is changing things, but it will take time.

I remember moving to HK many years ago from the US thinking - without reading the MPC program details - after I started flying CX for a few months of course I would inevitably start flying exclusively in premium cabins (without paying for it, of course). It's just a US thing because the carriers totally eroded the concept of premium cabin integrity with the insanely generous FF programs.