The only thing I can think of is if, and as always it's a big if, they want cheap used airplanes that allow them to maximize scope is the E190.

When DAL bought the C-series they backed out of the used Air Canada 190. So there are 20 of these for cheap. Jetblue has some orders coming up they (at least when I worked there in 13) said they would like to sell the new ones or sell the old ones as they get the new ones....I believe it~25. And finally Americain said they are not keeping the 190....20 more. That's 65 used cheap airframes that gets them ~40 more e175. Plus you already have a team of contractors for maintenance (all the E175 operators) while we get our program up. Sims that can be used and probably one of them has a program that we could buy to get training up and running quickly.

Or they are going to buy a few used 737 and 320 aircraft every year to fill the need.

I don't think this is a bad idea but it was nice looking at mainline growth. Now it's back to guessing what they are planning.