Certainly, the medical industry does not face the same competitive pressure from outside, but that is the nature of industry in general.
Rather than calling medicine a monopoly, it is more accurate to accuse heal care providers and practitioners of colluding to ensure prices are high. Monopolies by definition cannot collude since there would be nobody to collude with.
In the grand scheme of things, I believe medical costs are accurately priced and it is people's wages that are not adjusting correctly.