There will be teams of analytic nerds primed to figure out exactly how to maximise the current continuity, watching trends and what works and what doesn't and when the serialisation of these films and TV shows risk over saturation. They'll have hands on the dials to make it last as long as they can, and there will be suits overseeing the lore nerds that stand ready to reboot or put the whole thing on hiatus if they have to. One of the MCU's strengths is that it has people who care about the lore, the characters and the connective tissue, and people who want to mine the back catalogue for great entertainment and make household names of characters people have never even heard of. It won't always work, but there is so much material there that they have a lot of flexibility to move on and do new things when people get bored of stuff they've been living with for a long time or whatever.
Of course at some point the current audience will be old, and will want to introduce their kids and grandkids to these stories, and the old films are gonna look dated. Maybe some will seem timeless and fun, but when they can be done again, done differently, done better.. they probably will be.
It can be a multigenerational mythos that perseveres and reinvents itself the way the books do, but they need to ensure they keep it at least partly in the hands of people who care and don't just totally Star Wars it.
