I don't think anyone made any claims about unbiased samples...
If I were to say "I don't think the human experience has changed much because when I read Benjamin Franklin, I feel like I'm reading myself," I'm implicitly assuming that Franklin and I have representative experiences for our times. My experience might be more typical now than Franklin's was then; similarly, the Roman urbanite who reads very similarly to the American urbanite can mask the significant change in urbanization.
What, in a broad sense, does the future look like? We don't know, and while many have historically made predictions, the track record for such predictions is less than impressive. I have noted that there appear to be two main types of view about the future-- the "new future" and the "business-as-usual future." In order to simplify this discussion, let's restrict it only to the coming century-- the period between 2013 and 2113.
The "new future" is, generally speaking, the idea that the coming century is going to be very different from the present; the "business-as-usual future" is, generally speaking, the idea that the coming century is going to be very similar to the present.
Here are some characteristics of the new future:
Here are some characteristics of the business-as-usual future:
Reference class forecasting seems to indicate that the business-as-usual future is quite likely. But as we know, this is far from a textbook case of reference class forecasting, and applying such techniques may not be helpful. What, then, is a good method of establishing what you think the future will look like?