Would it surprise you to learn that your parents and/or grandparents were also a part of a "dying breed" of their own, and figured the world was doomed if left in your hands? Your generation figured things out and managed to get along. My generation is getting there. The next one will figure it out too.
Speaking of interest in old tractors in general, you have to consider that two generations ago a much larger swath of the population still lived on farms, so you guys got to see the equipment in action, what it could do, and experienced the sounds and smells associated. These days kids just see the tractors sitting there in a row, have never been anywhere near a farm, and we're expecting them to take the same level of interest?
I bet if you looked exclusively at farm families, the level of interest on a per-capita level is the same as it ever was. The main difference is that there are fewer and fewer farm families all the time as farms get larger and larger. Of course the interest has shifted to newer tractors. For a 70 year old guy, "Granddad's tractor" might have been an F20. For a 60 year old guy, it could be an M. For a 50 year old guy, it might be a 560. For a 40 year old guy, it would be an 856. For a 30 year old guy, it's a 1086. For a 20 year old guy, it's a 7130 Magnum.