That's the big question. I wish I knew. Right now these partnerships seem very tenuous, and this pilot group has seen partnerships like these fall apart in the past (Volaris) without ever realizing any real benefit. Without codeshare, it doesn't feel like it's completely solid. I imagine there are about 100 things that have to happen prior to something like that taking place, though, and we don't see any of it.
If this does end up working out, I am sure they would love to start heading in that direction. Watterson is a big fan of expanding the brand through partnerships. SWA is a big ship with a tiny rudder, though.
Like Ref mentioned, you can't just buy a bunch of 787s and start selling flights to markets where you have zero customers. This is definitely a precursor to any expansion in that arena. Time will tell if it works out.