I guess it depends on what you mean by "easily", but Putin could very much just say "fuck this" and turn off the war machine in one day and it's not at all clear to me that there would be much consequential blowback other than the personal humiliation of one man.

Would other countries now decide to attack Russia? Of course not. Would the oligarchs flip out and have him assassinated? No. Would the West disassemble the sanctioning apparatus? Eventually.

But the real downside is just simple humiliation and to prevent that, they will continue sacrificing young men.

Politics is a fucked up game.