Because the company uses quite a lot of administrative pressure (patent trolling, vendor's bullying etc etc), hence the market is not competitive.

You are talking about competitive markets here, not information asymmetry. I see no evidence that monopolies are the outcome of asymmetry of knowledge, but rather that they are the outcomes of significant administrative measures like license-bullying or patent-trolling.

The only markets that have the problem of information asymmetry are lemon markets.

> And these are industries where it's reasonably easy to pick and choose compared to trying to switch hospitals or doctors part way through your treatment.

It's way easier to change a doctor than to change a car. There are only few conditions which restrain one from bargaining: heart attacks and other severe conditions, and these should be treated differently.

But in case of the vast majority of diseases from common cold to Epstein-Barr changing the doctor and bargaining is even simpler than in most other markets.

But again, bargaining power has nothing to do with information asymmetry as well.