One of the reasons senior military people in big nations don't want to get involved in a shooting war is that the purpose of having a strong military is to deter wars they don't want. Once their nation starts shooting, it's proof that their deterrent failed. Then they run the risk of losing, or failing to win decisively, which is the same as losing, for a big nation. Another reason is that their strategies, tactics and equipment are exposed to enemies and any other observers with spy satellites, which means just about every other nation on earth. NATO is pricking up priceless information on Russia's order of battle, capabilities, armaments and support infrastructure--and they're cranking what they learn into their own strategies and plans. It's a two-way street: even as they're being beaten, the Russians are learning about NATO's strengths and equipment as they're being used by NATO's proxy, Ukraine.