Earlier quoted context omitted.
Fair enough, I read it wrong. When I read "commons based" I assume the word commons to mean public property, or Commonwealth concepts. And while Wikipedia doesn't copyright its material, it's still very much a private enterprise, despite depending on volunteers to add content. There are still paid employees of Wikipedia that ultimately manage it. It's not entirely decentralized in that sense. I think your definition…
No, there are paid employees of the Wikimedia Foundation, but not of Wikipedia. They do not ultimately manage Wikipedia, just its hosting; an ArbCom ultimately manages each Wikipedia, although there are the predictable and tiresome power struggles from time to time. However, that's ultimately irrelevant — what counts is that Wikipedia isn't written by employees and isn't owned by the owners of the means of production…
"Characteristics central to capitalism include private property, capital accumulation, wage labor, voluntary exchange, a price system and competitive markets."
Capital accumulation is an emergent property of private property. If you can own things, and government protects that and is prohibited from seizing property based on arbitrary factors, then capitalism emerges by default. It's not a "command-based" economy once private property and individual rights are established.
Markets aren't centrally managed in any way, they simply emerge as a property of people trading private property. That employees trade time for someone's else's private property (cash) is just a system that tends to work. I think there's other systems, it's certainly not the only way to organize, but it seems weird to say that it's non-capitalist. When I join a volunteer based organization, and donate my labor, it doesn't mean it's non-capitalist. The organization has simply chosen to give away IP rather than give away services (as a homeless shelter or food bank might do).