I went to a casino 2 weeks ago and it was interesting to see the WMS and Bally slot machines.
The Bally ones have the exact same logo as later Bally machines like Cactus Canyon. Slots seem to have the same kinds of innovations pinballs do, like an LCD "backglass" and generic art on the sides to change up the game while keeping the same machine.
I really don't think they have any interest in getting back in the pinball business. When you see that many machines in a Wal-Mart sized building, and think of how many others just like that are out there, I don't think there's any sense for them in getting up to speed to produce 5000 pinballs a year.