I think the author is wrong in thinking a "swiped at the door" and "no sales staff" is a better model.

Most gyms make their money locking people into annual contracts in exchange for a slightly lower monthly fee. This is especially true for "full-featured" gyms with lots of classes and staff.

The only way his idea works is for the 24 hour/keycard type of gym where only 1 employee is needed and there are no instructors necessary. (like SnapFitness)

I'd like to see some actual creative pricing based on actually going to the gym. For example, if you check in 100 out of your first 180 days, then your rate drops $5 a month. Or your rate drops $1 for every 5 pounds you lose (with a cap of course).