We all collectively own the funds, and if we ever want to lower yearly rates or pay our members dividends from surpluses, members are free to put it to a vote.
Part of the reason we run a surplus is to deal with any unexpected costs (they don't just scale with users, but also the popularity of users on our server), but FWIW I think we should open up a pay-what-you-can tier much like social.coop has. Thanks for reminding me, I'll send it to the coop for consideration.