I think KTF was a major comeback album just because the people in that era didn't have many medias where to get the news. Today we have something called INTERNET. In 1992 or before I think this word was just in Bill Gates head (in the pessimistic way... he was the first who didn't believe in internet at the beginning).
From These days to Crush, we all had more or less news from the web that informed us about what was going on with the band members, and in fact we didn't think to a band split up. Not as much as the 1990 people was thinking. I'm not sure of my english, but I think you understand me.
By the way I think that the Jon's and Richie's solo albums, especially in 1990-91, left space to a Bon Jovi split up policy, more than in 1997-98 with Destination Anywhere and Undiscovered Soul, because of the internet. The magazines and all the press weren't immediate as the internet is!
So, finally maybe KTF was a comeback album for the fans, and Crush was a comeback album for the general public!