particularly in the shadow of a hub. If American came in it would fly to LAS and PHX, United DEN and SFO or maybe only one.
For example ISP, Long Island Regional Airport, for SW flies to BWI, FLL and maybe TPA, granted this on 737 and not regional planes. But Long Island has a population of 8 million, 4 Million if you only count 'true' Long Island--this is more than Utah's whole pop. Regional airports fly to one or two hubs max.
I don't think the cost of Delta flying from Provo to MSP is cheaper than from SLC given the scale and overhead required.
https://www.cougarboard.com/board/message.html?id=21402203