The difference is that this time, they've managed to anger a large part of every demographic. Last time, it was a certain type of person and the remainder just said "don't slam the door on your way out".
Voat's problem was that it became VERY political very quickly. Hopefully we won't see that happen again, but I'm sure some of these substitutes will end up that way.
I have a feeling in reality most of them will die out, but enthusiasts (especially tech enthusiasts) will keep one alive, sort of like reddit in the early days.
As I remember it, VOAT's userbase essentially got taken over by Neo-Nazis and/or nazi sympathizers. I thought it was great that reddit had competition and then that happened.
Hopefully this time is different. This time the exodus is more widespread where voat got populated when reddit started banning nazis, pedophiles and necrophiliacs