Consider how much the experience of camping changed when the gear got lighter. Maybe trading that rough, real feel for easy packing killed part of the point for some people. I mean, is convenience wiping out a certain kind of outdoor respect?
At Yellowstone last summer, I saw plenty of canvas tent rentals. They're heavier and cost more, but some campers prefer them for durability. Nylon is just more common now because it's lighter and cheaper.