My guess is that we'll see decreased frequency on a lot of RJ routes, rather than a contraction of destinations.
My home airport is Santa Barbara (SBA) and there's 6 departures a day right now (4 PHX and 2 LAS). Most of these are on CRJ900s and they're seldom full. Back when there were 2 less departures a day and the planes were mostly CRJ200s, it was serious sardine time on every flight.
All of that said, RJs make a lot of sense at SBA (and other similar airports like BFL, SBP, MRY) for a couple of reasons:
- They're too far (more than 100 miles) from "big" airports to make driving to one a viable option based on cost or time.
- Their isolation decreases competition and thus makes both companies and individuals willing to pay more than might otherwise.
Frankly, on the PIT issue, I think we might see PIT or CLT reborn as a night hub, like LAS. It makes less sense, but it allows them to serve a range of destinations at, with better fleet utilization, lower prices thus appealing to a less schedule driven leisure traveler.