Earlier quoted context omitted.
Depends on whether you believe healthcare should be treated the same as other products in the marketplace, or if you think they are a public good.
I am trying to understand what you mean by "public good". It's not the formal economics meaning ( https://en.wikipedia.org/wiki/Public_good ), because healthcare clearly is excludable and rivalrous. The notion of a "public good" also isn't about how things should be treated, but more about how things necessarily are . It sort of seems you're making an argument unrelated to economics here, even though it's using words…
If one is to believe that healthcare products should be subject to market forces, then their prices should be variable in the same way other products are. In which case the answer to the question is, yes someone with a "niche" health problem would pay a substantially high price.
If however one believes that healthcare should not be subject to market forces, that is, it should be available to all equally (non-excludable) and cannot incur asymmetric costs between users (non-rival) then the answer is no, it would not be good.