"Some markets become obsolete when you remove capitalism" is not the same as "markets are only a thing under capitalism".

The real estate market would probably look much different and may even dissolve entirely if you forbid private ownership of real estate capital. I don't think this is a groundbreaking insight, I'm just clarifying for those who are careless about their use of words.

Yes but there's also people who think capitalism = things they don't like and don't bother to think about what the alternative truly looks like.

Straw men are not coming for your privately-owned home any time soon, friend.

Capitalism can also mean that politics shouldn't intervene when monopolies dominate markets. Then markets may also disappear in capitalism.

That's not what capitalism means. That's corporatism, if anything, assuming (as a sensible default) that corporations are the ones holding monopolies.