Yes, this is why governance in this system should be tied to your original earned points so it cannot, at least directly, be bought. The scheme that this system currently employs, for instance, is weight = min(earned_points, current_transferable_points).

So the only problem with a plutocratic system is that in real life the wrong people happen to be richest?

This is not governance of a state. It's governance of a private entity. Having token holders control the subreddit is no different than having shareholders govern a company. Assigning shares to owners, and having decisions made through shareholder vote, has proven to be the best way to govern large companies.

It’s not really clear if having a lot of these virtual tokens count the same as “wealth” though. Are there “wealthy” World of Warcraft players because WoW gold can turn into USD or are they just “rich?” I think it’s worth experimenting with at the very least.