I had heard a long time ago that they counted on members signing up, then never showing up, and forgetting to cancel their memberships.
The 2nd gym I joined was World's Gym. I absolutely loved it. One afternoon I walked in for a workout and all the dumbbells were piled up by the front entrance. Overnight it became a Planet Fitness. I had to eventually quit because the gym was very dark inside with depressing gloomy purple walls. I also once left a pair of nice winter gloves in the locker room that I had received as a gift. They told me they would put them in the lost and found. But when I came the next day, the gloves were gone.
I remember they had free pizza once a week in the evening. And free bagels and coffee once a week in the morning.