All possible examples would seem to be in one quadrant, because what we remember -- if anything -- is the time just before it in fact was made possible.
The alternative would be technologies that were never developed at all, most of which never had this sort of discussion and therefore wouldn't work as examples.
Take a more historical view, though, and you'll notice there were people claiming flight was near even decades before the Wright brothers.
Right, exactly as Eliezer says. There are plenty of examples in all four quadrants, so as a way of working out how near a technology is, this works less well than you'd like.
The alternative would be technologies that were never developed at all, most of which never had this sort of discussion and therefore wouldn't work as examples.
Take a more historical view, though, and you'll notice there were people claiming flight was near even decades before the Wright brothers.