You don't. A social network is a community, a home for people. If you kill it now then that's it, it's over, dead, finished, finito, you won't be able to reviv

You don't. A social network is a community, a home for people. If you kill it now then that's it, it's over, dead, finished, finito, you won't be able to revive it because you killed all your users trust. Hand it over to your active users or keep it going, and forget about investing, just ask for donations from your users, that will keep you going and you'll get more than you thought possible, not everything needs to be FB/Reddit scale.