There might be enough Yes fans willing to sit through the current band, but they're only just barely hanging in there. Will Yes fans be willing to go to a "Yes" show with the band lineup of Dylan Howe, Geoff Downes, Jon Davison, Billy Sherwood, and some other guitar player? Maybe they will, but I genuinely don't think so.
Actually what's more likely is that as soon as Howe stops touring the ARW folks will just take over and become the official band again. But even in their case I don't know if they will last another 10 years, Jon Anderson will be freaking 82 in 10 years.
The Beach Boys will be around as long as Mike Love is alive. Will he live that long? Maybe. He lives a pretty healthy lifestyle from what I know. I kinda doubt we'll have Brian Wilson for that much longer to be honest, but I hope he lives longer than Mike at least.
I think Rush will still be around. I don't think their current retirement will stick. They'll scale back to some extent and no longer do huge arena tours anymore but I think they'll get together to record another album or something.