wikipedia isn't a "platform" in that sense of the term, they don't make money by being a middleman between producers, consumers and advertisers.

They are super successful at gathering donations, right? I think their goal is fundamentally well-scoped to the sort budget they can hope to get just from donations.

I mean most of the value there is in text written by volunteers, which must not be so expensive to host (compared to, say, an image hosting site for example).