But I think that is the ultimate point of sanctions. If the government cares about the people at all, it will relent on what it's doing to ease the suffering by its people. OTOH, if the government doesn't care about its people, eventually the sanctions will get so bad that the people may lead a revolt against the government. Either way the sanctions have an effect on the country.

The biggest problem is that any leader who has made this kind of error in the first place is unlikely to back down, due to pride. In the case of a lunatic dictator, there's a chance that he will double down on his action to try to "win" and become a champion for his country. Or he may feel his back is against the wall and he has to fight back against the sanctioning country in a different way.

This is ultimately the direction that Japan took in launching the attack on Pearl Harbor, following the multiple embargoes that the US levied against them. That proved to be a strategic mistake for them. Let's hope that Putin has studied his history.