Of course the community driven, anarchic nature of Wikipedia is a threat to the status quo of capitalists dominating society. Musk can't stand this, because it shows how ultra wealthy, incompetent dicktators like him are unnecessary.
Wikipedia is anything but anarchy. There's so much bureaucracy it would surprise even Kafka.
I also don't think Elon's psyche is built around an abstract notion of economic systems. He's simply a narcissist that desires shiny things, in a very basic and unrefined way. Rich people just want to add baubles to their menagerie.
Wikipedia is by its own standards a propaganda organ for the status quo (a mainstream encyclopedia that summarizes mainstream science, history and journalism).