See I'd counter with the fact that Richie being incapable of doing anything coherent for a few years created things like the Lost Highway album in the first place, where Jon pretty much was going it alone. It's not just one factor, it's a combination of factors.

Richie's solo tour seems to have got him back in the groove though, and at long last.

Jon currently is having some sort of issues - whether vocally, confidence, sickness, I don't know. I've no doubt they'll work them out.