I think a platform such as Medium is an interesting topic for this. While the technology and platform itself have private owners, the product that Medium provides is an exchange, and ownership isn’t assigned in the traditional way. This gets a bit murky, but Medium could be described more as a market itself, rather than an entity existing in a broader market. My point is basically this:
Young people that feel that capitalism has failed them are unlikely to be convinced otherwise by the argument that Medium and other similar platforms are capitalist systems, because even if they technically are, they do not resemble what most people think of when they invoke images of capitalism.