To once again paraphrase Mark Twain, "the reports of the death of backpacking in the Smokies have been greatly exaggerated".
According to data collected by the National Park Service Visitor Use Statistics website, the number of backcountry overnight stays in the Smokies jumped by more than 13% in 2015, when compared to the prior year. Moreover, the 97,629 backcountry overnight stays recorded in last year was the highest count in the last 16 years.
Some people in the backpacking community thought that the sharp drop-off recorded in 2013 was a direct result of the backcountry fees that were implemented in February of that year. Although that may be true, that some backpackers were essentially boycotting the park in protest to the fees, that trend appears to have been reversed.
Here's a graphical look at backcountry overnight stay counts over the last 16 years: