Last year they upgraded almost 200 Captains. So far this year at 134. Word is 500 for next year. Not bad "growth" to skew the Captain seats for years to come. Without massive orders of aircraft it will be hard for the senior FAT FO's that will be uber senior) to see any upgrades when everything flattens out over the coming years.
Many of those upgrades are coming at a price. Unless they live or are willing to move west, they'll be commuting cross country to Capt reserve for decades, especially when the FAT guys can start moving left. We have a lot of guys
bypassing upgrade for this reason. I know 2 guys personally that upgraded, commuted for a while, and bid back to the right seat (not even a lance in one of the cases) for QOL reasons.
Being an FO at SW is not a bad gig, particularly a senior one at top scale. A senior FO, living in domicile can work less days (if you count commuting days as the jr capt) and make nearly as much as he would commuting to reserve. I think 128 tfp is the magic break even number for an FO to make the same as he would as a reserve Capt making 90ish. It's far easier to make 128 TFP (without even messing with POT stuff) as an in domicile, senior guy than it is to commute to 90 tfp on reserve on the other side of the country.
I know if my choice was being a senior FO in my domicile, or a jr. Capt on the other side of the country, I'd take the FO gig in a heartbeat.
The only downside is if you go out on medical, you get a lot more if you're a Capt than an FO.
As for the "flattish" comment, we're already there. If we're lucky. The 717s leaving negatively affects us too, as now we have to absorb all the AT pilots with roughly 1/3 the seats.