The problem about this idea of putting those franchises on ice for 20 years... who will even care then? Most kids these days never read comics or read books. Most haven't seen Star Wars stuff except what came out in recent years maybe, and to them it's just a pew-pew space vroom bunch of moving pictures like you can find a dime a dozen on all streaming platforms.
What made Star Wars special for us was that when it came out it WAS special. It stopped being special when every other company became able to produce similar special effects, especially these days when you can do all this shit in a green cube room with someone riding a green tarp for a mount, brandishing a green stick at something that has tennis balls for eyes so you can see where to swing.
If you just stop making Batman, Superman, or Star Wars stuff for 20 years, no one will care about it when it comes back eventually because it's antiquated stuff that mostly works out of nostalgia for the people who actually grew up with it.
The problem is they just keep shoveling out shitty content, which takes its own part in burying it even faster.
The solution would be to just take the time to make good content, putting stuff on ice never really works if the last thing before that was absolute shit (just ask Mass Effect 5 how it's doing).