I don't see Richie returning. Neither wants it. I don't think Richie misses the music or the touring or it wouldn't have taken years to complete his last project and RSO would have been playing wherever they could to build their brand, get some credibility and remake his name/image. Vanity projects are costly and do not work.
Jon provided the boundaries and rules Richie needed as a musician. Without Jon, Richie hasn't been the frontman he thinks he is as he doesn't have the extreme work ethic Jon is known for.
By the time Jon would even consider it as a last economic hurrah, Richie will be even more embarrassing to watch. Jon is smart. He knew he would get old on stage and he let his image evolve. Actually it is kind of weird as Jon and Phil are close in age and obviously it still works for Phil to be a rocker and even more so when he is with the Drills.
Richie wants to look and act like he did years ago and it doesn't work probably due to the effects of long-term drug/alcohol issues. Having said all this, I really like the guy and I have no interest in buying a ticket to see Bon Jovi without him.
You Europeans and your attitude. I remember when Richie walked, you were sure Jon would have to cancel the European tour. It was ok for Bon Jovi to play without Richie in the US but no way would it be acceptable for Europe. Bon Jovi toured Europe and sold tickets. Now this conversation is starting over yet again.