From starting out in 84 the band was all just album/tour, album/tour, album/tour. It peaked in an exhaustive 250+ shows world tour that ended 1990. There had been trouble with his long time relationship and today's wife. After the last scandalous gig in Mexico the members were burnt and pretty much fed up with each other and everyone left in a different direction. There were rumours the band would split up (which they never did).

Jon somehow lost track and I believe he didn't exactly know how and why. There was also trouble with the bands long time manager. Jon somehow needed to clean up what he's achieved so far, to find out what was worth keeping and what he needed to get rid of. He went on vacation with a few friends on motorcycles through the Southwest. He needed to come down. He found that the music itself is still what he loves and found the valve for his creativity in his much respected first solo approach that brought him a Grammy and an Academy Award nomination.

He recognized that he was good at what he was doing and that there was a good band, too. They recognized that the basics were still stood, they are all mates and that it was just too much hype for their bodies and minds. They found back together and recorded their first comeback record KTF.
Since then they all have been very careful to keep things under their control and not let things control them.

Not all very factual, but this is pretty much how I would sum it up. Hope it hepls.