Jovi still seem relevant to the housewife market, they have longevity. My missus still likes them after 30-ish years and seems not to care about the quality of each new release, or at least she didn't take offence to it (unlike most of us male Jovi fans who constantly hark back to Slippery/New Jersey/Faith era). She just loves them no matter what, kind of a band for life.
The others just seem to be seen as retro type acts. Certainly here in the UK I think that even the die hard Def Leppard fans struggled to stomach anything after Slang, whereas the casual fans had long left the party by that stage.
Either way, two things are for certain a) jovi will forever be slated by fans of 80's style rock (this forum is proof of that), and b) jovi will continue to sell out tours and have relatively succesfull record sales for years to come, they have found a formula that works musically, they are promoted incredibly well still, and maybe the basic fact that the ladies of the land see Jon Bon Jovi as a good looking, ageing rocker, rough round the edges yet considered clean cut.....maybe thats exactly what they want the band to be, so they'll buy the albums, t-shirts and concert tickets which in turn gives,them the financial clout to continue to make records.
Unfortunately Def Leppard and Journey will not get the mainstream exposure as Jovi do, making them even more and more irrelevant to the record buying public. these bands are huge in our little clique, but in the grand scheme of the industry they are history. time moves on, very few bands/artists continue to be successful into their 3rd or 4th decade.