They'll be wrong until the moment they're right. The USSR looked similarly durable in the 1980s, and the few voices saying it was rotten at the core and on the verge of collapse were waved off.
I had first hand reports from the field in the 1980's that the soviet union was falling apart socially and economically. Friend was a Russian studies major, spent two years in the soviet union. Another friend also spent six months there. And one of the board members of my old old company was in the oil and gas business and traveled to Russian a lot.