Well, it is good that Mearsheimer arrives to conclusions about the damage (he was on record for years that Russia has a "mediocre" military).
"Neutral Ukraine" stopped being "solution" about two months ago and it is not about Ukraine anymore. In fact, it never was from the git go in 2014. It is, indeed, an existential struggle for Russia and Putin is one of the dovish ones in Russian leadership. Moreover, what Mearsheimer fails to understand, that Russia didn't even roll out big guns and they are being kept in reserve in case Russia decides, which appears to be the case, to "expand" on her military-political objectives for SMO and is now in the mode of breaking up NATO. In this case, it really doesn't matter what the US wants or cares about--it is all connected to the escalation dominance Russia possesses and I warned about it as early as 2015-16. It is not about Putin, it is about Russian people, as a nation and we are long past the point of any negotiations about Ukraine. As I write for 8 years in this blog--the subject of negotiations is what will be the conditions of surrender of the combined West. I hope Mearsheimer begins to understand this.