Ah, that's the billion-dollar question. In most of the revolutions, the army, not the citizenry, was the one who went against the ruler. For example that's why Putin kept his army weakened and ineffective and had Wagner force(which still tried to revolt).

They're hoping AI and robotics will be capable of handling security by that time.

Treat them well enough, and they become the new middle class. Not rich, but not poor enough to revolt.