My problem with Mearsheimer and the other realists is they have a very poor explanation why the status quo changes. Yes great power competition explains why tensions are high but does little explain why and when they spill over to war.
Notably absent from this article is any discussion of "why now?". Commenters in the thread are saying that his 2015 article on the subject could be written last week. That's precisely the issue. Why did Russia raise the stakes in December? Sure, NATO's eastward push has demonstrably increased tensions but the eastward push has been frozen since about 2014 since countries can't join NATO if they have territorial conflicts. If anything tensions should have been easing with a new, slightly more Russia friendly, German Chancellor, the nearing completion of NordStream2 and President Zelsynsky ran on a platform of improved relations with Moscow.
If you just look at the independent variables you inevitably are going to make conclusions from ideology rather than testing hypothesis. This type of article is the international relations equivalent off economists have predicted 5 of the last 3 recessions.
You can also see this weakness play out in Mearshimer's answers to journalists questions about the agency of Ukrainians in this article. He dodges the question and points to a speech from George W Bush in 2008, which was 15 years and 3 presidents ago, and prior to the current Ukrainian regime. In contrast he can't explain why the Baltics entering NATO did not trigger the same reaction. If we're going to look at history we can't ignore that these Eastern European Countries have endogenous reasons for joining NATO including the USSR and then Russia's long history of invading those countries.