And it wasn't entrusted primarily to Roncalli. Pius XI and Pius XII both had ample opportunity to perform the consecration of Russia, which would have averted the crisis foretold in the Third Secret. I think that the Third Secret was primarily a message to the pope about what would happen if they did not perform the consecration, and secondarily she knew that enough of it would be leaked to console the faithful. Pius XII famously said, "After me, the deluge." ... and yet failed to perform the consecration that would have prevented said deluge. He knew it was coming because of the Third Secret and not due to some personal gift of prophecy.