My opinion is clear on this I think. It was crystal clear to us that Russia would react if Ukraine lost its neutrality. In an ideal world every country would be free to decide its fate. But we don't leave in an utopia. See how US reacted in Cuba for example. It is what it is. Knowing that, why would we try to expand knowing that 100's of thousands would die? Don't get me wrong, I am not with Russia. As a Greek we have in our hearts both Ukraine and Russia. We have large population living in each of the two countries and this war is painful to see. At the end of the day Russia shouldn't had invaded and should just f%ck off Ukraine already. I feel that we, as NATO, could have avoided this war and that's why iam blaming us, the "adults" in the room.
As for the mass extinction I believe 100% that Putin will force EU and US to chose if they want to trade Paris - Washington- London etc for Moscow. I mean he has told it clear as day that Russia can't win a conventional war against an alliance. His track record shows that he doesn't bluff. World leaders seem to understand this and thats why they don't declare war to Russia.