There is another likely scenario, Putin dies for some reason. Replacement gives up on the invasion.
The only force that can stop him is army now and I reeeally don’t think this is what any of the sides (except them) would want because it’s them who pushed him or at least helped him to start the war, obviously. We don’t want another Myanmar, but 100x in size and with a bunch of nuclear warheads.
Discussions around the Magnitsky_Act* went into detail about this, and it came up again during the Trump Impeachments.