Endgame is decentralizing the internet and perhaps non-internet protocols. Even if the probability of a decentralized social network working is small, the upside in the case it does work is so large that it's worth the bet
ie: 100% downside vs 10,000%+ upside. If only 1 out of 100 such bets works out they break even. If 2 they have a profitable fund, 3+ they have knocked it out of the park.