Sure the US3 are run by *******s, but so are most airlines globally. Admittedly they don't have really good service, but it is acceptable. The problem with the US3 and US airlines in general is that they are large. Really large. 1000 planes and 90k employees large. And with those numbers you are gonna have several thousand people with entirely different personalities, which translates to some crews being the best there ever was and some others just collecting paychecks. Which happens to many airlines. But when you have such large fleets you have many more passengers, aka more people are gonna observe this phenomenon, and in this day and age, when everything is uploaded or recorded somewhere we hear more and more things about them. Like we hear more of WN's perky and funny FA's, we're gonna hear more stories of people getting thrown off planes, and in the post-Dao era that automatically translates to the airline being at fault, even if it's not actually true. And also the fact that the US airlines, and especially the US3, have so many employees, it's hard to keep consistency on the service, let alone the crew's attitude. Sure, US FA's have been abusing their power all the time post-9/11, but bad service doesn't define them. Delta is keeping 9-abreast 777's, which beats most airlines worldwide, UA has half their Y cabins allocated to a seat with extra legroom at little cost (which is a feature on all US airlines nowadays, which beats what most other airlines do), and AA has been improving quite a bit lately IMO. And in terms of J UA and DL both have very innovative and competitive products. I think the US3 could imrpove as much as the next guy, but they definitely aren't bad.
P.S. Never flown on any US airline so this is purely by what I've heard.