Naughty Dog will some day shut down the servers.
It's a pretty inevitable conclusion. Even if it lasts much more than expected, let's say once PS8 launches in 2040, and Naughty Dog thinks no one cares about Factions anymore, they'll shut it down.
I hope when that day comes Naughty Dog will have to suffer a storm of shit never seen before. The way they handled Factions (announcing it as part of Part 2, canceling it for Part 2 because they'll release it as stand alone, canceling the stand alone, never releasing Factions with Part 1) is downright disgusting. I still remember some post where some PR guy said "guis we LOVE Factions as much as you guis". Yeah Dog that's how you show love to people you love, by ignoring something until it finally dies?
It's no coincidence people started reverse engineering a Part 2 multiplayer. The fans know in their bones, even if only subconsciously, that one day they'll have no one to rely on but themselves.