I dont think NATO would kick Russia's arse actually. European counties have for years been cutting back on defence spending. The UK is as weak as hell, we have literally no military left, and Putin knows the US and UK are busy in other countries abroad and have stretched resources. Other European countries have also cut back on their military.
Then there are the old USSR countries, would they really side with Europe in a war with Russia or would its people, like some in the Ukraine side with Russia?
Who knows, but we need to seriously stop thinking Russia isnt strong militarily. Its very strong, and has some very advanced weapons.