Not your screen monkey (he/him)
...First, let me state that I am not commenting on the quality of any edition or upon print vs. digital format. I am also not commenting on the quality of any business decision made by either company.
...I doubt that Paizo would be willing to work for Wizards again. They did a good job turning out quality Dungeon and Dragon magazines during 3rd edition. When 4th edition came out, Wizards took back both magazines and went digital with them.
...Pathfinder was, in large part, the result of Wizards leaving Paizo without much in the terms of marketable products. I just don't think that Paizo would be willing to hitch the future of their company to a Wizards project again.
Yeah, I think any long term relationship with Paizo being dependent on WotC licensing is a non-starter. They got burned by it once, they won't get burned by it again.
I could see individuals from Paizo doing some freelance work for WotC, though. I could even see Paizo putting some resources into writing adventures or other materials that are reasonably compatible with both D&D and PF - dual stat, substantial conversion notes, and so on. But I think any of that would probably be dependent on an open-enough license with D&D that Paizo has the ability to control the resulting IP and work at their own schedule. Alternatively, setting up a limited term, very specific license to do some specific work for a specific time might be worthwhile for Paizo. I'm thinking of the Green Ronin license to do DC Adventures - 4 books and the license was done. I wouldn't mind Paizo getting involved in a contract like that to do a hard cover compiled edition of Age of Worms or Savage Tide - in PF and D&D5 versions. But, again, this would have to be a specific, limited contract and not something to build a long-term business model on.