This would apply rather nicely to people predicting the future of China today.
All these clever men were prophesying with every variety of ingenuity what would happen soon, and they all did it in the same way, by taking something they saw “going strong,” as the saying is, and carrying it as far as ever their imagination could stretch. This, they said, was the true and simple way of anticipating the future. “Just as,” said Dr. Pellkins, in a fine passage,—”just as when we see a pig in a litter larger than the other pigs, we know that by an unalterable law of the Inscrutable it will some day be larger than an elephant,—just as we know, when we see weeds and dandelions growing more and more thickly in a garden, that they must, in spite of all our efforts, grow taller than the chimney-pots and swallow the house from sight, so we know and reverently acknowledge, that when any power in human politics has shown for any period of time any considerable activity, it will go on until it reaches to the sky.”
From “The Napoleon of Notting Hill.”