As I said long discussion needed.
Rubber domes are not all the same, there are zillions of them, the cheapest one starts from 3 or 4 $ and ends with Topre.
But even if we limit to the membrane ones there is an huge chioce, i have a client that owns more or less 70 PCs it's company grew slowly and so their PCs so in this company there are more or less 70 different keyboards, some are in the reservation sector where they are used continuously for 12h per day and most of them are cheap acer or samsung rubber domes that are working w/o a single glitch since 1995 or 1998, other ones lasted just 2 or 3 years, hardly a cherry MX board will last such time w/o a single switch broken or stuck, w/o losing evenness or tactility, w/o an oxidized contact or a bad soldering.
What changes is the fixability (as you said) a switch can be replaced, lubed, cleaned, but this hardly is an interesting matter for a large company, when you can swap a whole keyboard for 5$ who cares about replacing a switch that cost almost the same ?
We want to talk about legends ? You remember that filco ones will last 3 months when some cheap rubber dome are practically undeletable ?
Obviously even mech are not all the same there are the Buckling springs that are damn robust, there are other kind of switches, there are the cherry linear that surely will last more than the tactile ones and so on.
But the conclusion is that mech are meant to be cosed with the heart, not with the brain, trying to rationalize usually lead to tell lies to herself.