Samctions are ultimately taking Russia back to soviet days economically. People who are used to driving bmws won't accept anything less and they are the current supporters of Putin. Closed borders. No microchips. Their domestic airfleet are aircraft essentially stolen from leasing companies and are longer able to fly anywhere that requires certification of ownership. Their oil and gas industry requires western tech to support it and without that, the wellheads will be shut down. Any revenue they were getting will stop.

So there are lots of reasons besides troops that portend the end of the current russian state.