as the legacy carriers have embraced many of the aspects of the ULCC's, it has depressed the overall level of service across the board. They have used it as way to introduce RyanAir-type policies in more areas than just the bare-bones economy tickets. I think it shows in how their staff interact with all customers, and it can't help but affect their staff when they have to deal with things like baggage issues that they didn't have to before. I think it probably erodes the pride of many in their employer.

Last time I was on a TATL flight on United in business class, the treatment I received as a passenger wasn't commensurate with the fare class. It felt like economy plus with a bigger seat and a cloth napkin. The check-in experience had a shorter and faster line, but the treatment felt the same. The flight attendants were not particularly pleasant and the food sucked.

Similarly the last time I was in economy on a United flight, even though I was on a full-fare ticket, my experience was exactly the same as the rest of the people who were being treated very average by a bunch of flight attendants who, nearly to a person, appeared to hate their job. So, maybe I was able to check a bag, but my overall experience was not different from basic economy.

TLDR; you may pay for a better experience, but my experience with legacies doesn't mean you'll get it.