Does it matter if things are out of sync, or if you do a particular cleanup more often than is minimally required? Usually it doesn't.I'm just saying for those that maintain or replace components as needed, a teardown is unnecessary. Maintenance will be out of sync so there's no way to avoid piecemeal maintenance throughout the riding season that will address crud build up in all the nooks and crannies. I check pivots when I service the shock. Check the headset when I pull the fork for a damper service. I check and clean the bb when I replace the chainring. The only other place that gets build up is behind the cassette. I'll pull that periodically because they last so long I can't wait until it's worn out. Cables and housing replaced when needed. Nasty weather dictates anything outside that regime. Because components have out of sync maintenance needs, everything a teardown accomplishes will be address it's just piecemeal instead of all at once.
If you want to break down the bike when you're not riding it so you can be more thorough, then have at it.
A lot of people's cleaning/maintenance routines will depend on riding conditions, too, and not just mileage. I'm checking/cleaning/replacing grease around my headset and bb bearings with some regularity riding in Pisgah. Same with my freehub pawls. Folks riding in the desert wouldn't need to be checking those things as often.
Plus, some people like a cleaner bike than others. I got over trying to keep my bike pristine a long time ago, but I understand it. I focus my cleaning/maintenance efforts in specific spots. Otherwise, meh. If someone else wants to, then that's up to them. Unnecessary, maybe, but if it makes them happy, who am I to harp on them over it?