As I said, long distance hiking numbers seem to be going up (the AT!!!!) but over all backpacking numbers ARE going down
Figures from the NPS, outdoor orgs and outdoor industry officials show the trend of "done in a day activities" dominating outdoor recreation.
(HIKING is a a day use activity and is not backpacking)
I could google the numbers, but there are plenty of threads on this topic already here on WB.
The quick and dirty way to see this in reality is to see the gear that make up the majority of sales at most outdoor stores: It is for day use activities and "life style" clothing.