Another failing Magic Fitness Pill?
Most people - for diverse reasons - simply don't want to do any work to be fit. They don't want to change their diet, exercise, any of that tedious stuff. Most diets and other fads are driven by people looking for something easy they can do and magically lose weight (notice, NOT "be fit"). Many of the people actually doing exercise are putting in the minimum effort to say they're done it, not working hard for real change.
I suspect fitness trackers are the current Magic Pill Prospect. But like other fitness plans, folks eventually find out that Work Is Involved if you want real results. The band doesn't make one magically slim without effort, so it goes in the drawer. The devices are victims of unreasonable expectations.
At least an unused Fitbit takes up less space than the millions of dust-covered rowing machines, treadmills, bikes, ab-rollers and other once-hopeful Magic Fitness gadgets cluttering garages.