No, it really isn't.
The damage to Russia's economy is pretty heavy right now, but Russia's population won't starve and all indications appear to be that Putin's popularity has grown, not shrunk since the war began. Putin didn't slap his own country with sanctions. The West did. And all Putin has to do is to point at the hypocrisy; no-one slapped the US with sanctions when it intervened in Libya. No one slapped the US with sanctions when it provides assistance to the Saudi's with their war in Yemen. Or any other American interventions within the Middle East. To the average Russian citizen, that's going to be a rather convincing argument.
More to the point, the Americans can't shut Russia out of the global economy. Russia's wheat, fertilizer, and oil/gas exports are just too large and important to the rest of the world. In some cases, several African countries are 100% reliant upon Ukrainian and Russian wheat exports. Using SWIFT against the Russians was damned foolish, because the Chinese know they're going to be next and instead of scrambling when the US finally unleashes it upon them, they're going to let the Russians beta test the first post-American Dollar system.