Curiously, about what percent of UA flying is comprised of UX vs Maineline both in terms of total passengers moved and aircraft movements. Is there way to grab this data anywhere?

I ask because regional flying seems to be a big factor in the legacies in the US yet regionals are seemingly always given the shaft in terms of customer experience: poor if any food options, incredibly cramped gates/terminals at airports, outsourced/less experienced airport staff, high delay/cancellation rates? (and yes smaller planes, but I take that to be an acceptable choice in order to effectively serve smaller markets). Why alienate such a (maybe) large segment of your customers?

Is it because they simply can and choose money by doing so? Is it because it's too hard to do quality control with subsidiaries? Because regional flying was never envisioned to be as extensive/long flights as today?

It never made sense why airlines segregate their brand into two classes of service and everyone seems to go along with it, including airport designers ("Oh yes, we can have 6 50-seat jets board out of the same time in 3 adjacent gates, no problem, it's regional!" I'm looking at you, concourse F in ORD, or even the newish regional extension at DEN"