Yeah, gyms and fitness centers make a huge amount of money on no-shows.
They count on the majority of people who buy memberships to eventually (and often quite swiftly) end up paying for months on end when they do not use the gym.
Truth-be-told, the gyms would rather have members who use the gym and reach their fitness goals, etc. Not only do they pay dues long-term, but they buy supplements, equipment and time with personal trainers. But, the large number of no-shows keep revenue coming in, and there's no drain on resources or wear-and-tear on equipment.
Michael