Point 1: SWA's customers (like everyone's customers) want the cheapest ticket they can buy. As of now, SWA management doesn't have the need to pursue the RJ option. Who knows what it will look like 10 years from now. If SWA can find a way to outsource to RJs, I think they will.

Point 2: 10-15 years ago, mainline flew 70-100 seat F-28s, DC-9s, and F-100s at reasonable pay.