I am not a Russia scholar, but this charge isn't fair. To quote the conclusion of my old ( 1977) A History of Russia, by Riasanovsky:

the Soviet system is not likely to last, not likely to change fundamentally by evolution, and not likely to be overthrown by a revolution. History, to be sure, has a way of advancing even when that means leaving historians behind.

Riasanovsky was right- there was no change by evolution, no revolutionary overthrow, and the Soviet Union did not last. There were plenty of problems he and others had seen...the stifling of culture and lives of citizens, poor standards of living, tensions from the nationalities ( Georgia, Kazahkstan, etc.), the economy growing beyond the simplistic Soviet directives to always maximize production...and these were an important part of the splintering when it happened. But the Soviet Union had somehow bumped along for decades, and it was possible to imagine it somehow bumping along for some years to come. Anyone who wants to hold Russia scholars accountable for not being able to predict precisely WHEN it would come apart perhaps should look into how successful we have been at predicting earthquakes, the formation of hurricanes, and other chaotic, complex events.