NATO is first and foremost a tool of American power in Europe and against Russia. If the geopolitical landscape changed so much that Russia decided to join the EU and was accepted, I think it would have to mean that the EU/Europe had shifted (back) to standing up on its own.

> with the economy of the similar size to Germany

Russia's economy is not that big. Nominal GDP is between Spain and Italy.

Sure, but that's only because Russian and US foreign policy goals are so opposed.

Other than their territorial ambitions in Europe this need not be the case.

The US want to keep control of Europe, that's partly what NATO is for. There's no reason for Russia to be OK with that. In fact no European country should be OK with that but for historically reasons I think they reckon that this is better than the fear of letting the "good old ways" (i.e. France or Germany trying to take over) come back, although Germany has pretty much taken over by peaceful means at this point, especially since Brexit...

It's not correct to say that all Western European countries were/are OK with US power and presence. The major powers were divided on that. Germany obviously did not really have any say, France did not want the US to stay, the UK thought that it'd help them look more important than they had become. But smaller countries may see the US as a guarantee against larger neighbours trying to invade again, as I mentioned, a bit like South Korea does.

Germany, and also that other country. https://en.wikipedia.org/wiki/Molotov%E2%80%93Ribbentrop_Pac...