By "maintenance mode" you mean shipping more features per year than the pre-Elon Twitter? Remember, the pre-Elon Twitter was completely stagnant and seemingly unable to ship even the most desired features.
Musk has openly said many times he wants X to be an "everything app" and sees huge growth in its future. What makes you think he ever intended to put it in "maintenance mode"?
Musk didn't buy Twitter to make money or learn how to run a successful business. "Keep on trucking" isn't what Twitter is supposed to be doing right now. 20% workforce is more than enough to run the operation in maintenance mode, which is exactly what's being asked for.
How many dev-ops roles would it take to just keep the lights on at your org? A dozen? Three? You certainly wouldn't have a need for decision-makers or heavy lifters.