Either the Ukrainian military succeeds in pacifying and controlling the its eastern regions or eventually they will be incorporated into Russia. Realpolitik trumps rhetoric.
Russia has forced a war on Ukraine, but so far, Russia itself remains completely untouched itself.
Putin has gambled that forcing a civil war in a neighboring country will not involve him or his country, and so far, he is correct.
Ukraine somehow needs to bring war to Russia. Then Putin will face some serious risk in his position and will only then think twice about dismembering Ukraine.