Who needs your prosperity promises if you turn 5 million of their compatriots into refugees, captives, or worse? Russians've seen that kind of "prosperity" in the 90s and I don't think they're going to fall for this one more time.
If you think Ukraine have won the war, let's see how they arrange the life on all the lands that they have already reclaimed.
No one is going to fall for the promises of the USSR system, that's for sure.
5 million Ukrainians already run away from it. I think they are doing great, much better than those who stayed in a war zone (where many were brutally tortured or killed). As soon as the war ends, many of them will come back. In fact, many are already returning.
If you think Ukraine have won the war, let's see how they arrange the life on all the lands that they have already reclaimed.