Oh, they’d never do anything as sinister as that. That may still be illegal (if the ultra-rich lobbying hasn’t taken care of that obstacle by that point).
Instead, they’ll just make sure that whatever essential core service they’ve built a monopoly in by just muscling the poorer competitors out of the race will cease to be offered to you if you refuse to hand all your money over to them.
See also: insulin, hospital treatment, etc. This is just a new playing field to find old prey in.