That’s true the trends go back further, but I think it was still possible to turn things around in the late 80s if more competent people were in charge. In my opinion, the most important aspect of USSR that needs to be analyzed going forward is how to improve the political system in order to keep opportunists and the incompetent out of positions of power. It’s a general unsolved problem pretty much all human societies have that quality of leadership declines when the times are good.
I doubt if it could be just entirely averted, but if we got Deng instead of Gorba… on the other hand, USSR and Warsaw Pact wasn’t China, imperialists were way too invested into toppling and looting it, they would never left us just be there and rule ourselves on the promise of capitalism.
A lot of it was the aging of the population and leadership, combined with loss of political knowledge caused by the loss of an entire generation during ww2.