There are plenty of rules that require enforcement that are not petty or stupid: requiring seat belts during take off, landing, and turbulence, or enforcing no smoking policies.

I am reminded of the discussion here a while back about Airbnb and hotel regulation: some of New York's regulations governing hotels are stupid and petty...but others come out of a genuine desire for safety (like adequate fire escapes and sprinklers). Same with the FAA: some rules are outdated, and silly: planes should be able to cope with personal electronic devices...but others are to ensure previous disasters don't happen again.

I'm sure some airlines would happily have fewer cabin crew if the FAA would let them: yes, they can sell in-flight items, but that probably doesn't break even on the cost of employing them.

I always thought just letting flyers pick out their cold beverage at the gate before takeoff would replace flight attendants (domestic; international still serves food).