If you give up on the idea that there has to be one main universe, then it's more likely that your favourite universe gets to live and exist alongside the other universes.
I disagree, that's all. I think without a main universe, there will be no real universes. Instead, each run will have it's own continuity, and with every change in creative team, there'll be a new run and nothing from the old will matter anymore. Maybe that won't happen, but I think it's the most likely outcome. Well, that or times when the Green Lantern writer says it takes place in the same universe as Batman and then the Batman writer says no it doesn't.

So I prefer to believe that my favourite universes still exist and can be returned to at any time, without the need for continuity breaking crisis events. I would much rather that DC published comics that were each set in different continuities, so I'd have a chance of getting the one I like.
I just think we're more apt to end up with no continuing continuities, rather than several. Instead there will dozens of short-term (for one series, none lasting more than 5 years and many less than 2 years) continuities that never get revisited.