The answer is quite simply that where complexity exceeds the regular person's interest, there will be a cathedral.

It's not about capitalism or incentives. Humans have cognitive limits and technology is very low on the list for most. They want someone else to handle complexity so they can focus on their lives. Medieval guilds, religious hierarchies, tribal councils, your distribution's package repository, it's all cathedrals. Humans have always delegated complexity to trusted authorities.

The 25% who 'care about privacy or ownership' mostly just say they care. When actually faced with configuring their own email server or compiling their own kernel, 24% of that 25% immediately choose the cathedral. You know the type, the people who attend FOSDEM carrying MacBooks. The incentives don't create the demand for cathedrals, but respond to it. Even in a post-scarcity commune, someone would emerge to handle the complex stuff while everyone else gratefully lets them.

The bazaar doesn't lose because of capitalism. It loses because most humans, given the choice between understanding something complex or trusting someone else to handle it, will choose trust every time. Not just trust, but CYA (I'm not responsible for something I don't fully understand) every time. Why do you think AI is successful? I'd rather even trust a blathering robot than myself. It turns out, people like being told what to do on things they don't care about.