Your users flocked to you out of trust, and the moment you turn over the keys, you're hanging your users out to dry. Unless you're really just looking to get out out, keep on keeping on, especially if your userbase is willing to pay you to maintain the space.
If you're really not into it anymore, go to the community first for people to step up. If no one steps up; shut it down.
There is no happy end selling your userbase to VC. You're just handing all that trust you built up over to sharks, and tainting your own name as someone looking for an easy exit at everyone else's expense.
Don't be that person. If maintaining the network is too draining, kill it, and dd the drives/infra. It's better that way. Lose the keys, and move on.