I don't understand why American gyms are set up in this way when in the UK almost everywhere lets you pay by the month with no cancellation fee.

One of our biggest chains Puregym has something like a 20 quid joining fee that you can usually get around with a promotion. That's it. Most of the gyms have day passes for about £7 as well, more expensive in bigger cities sure.

I don't understand how the "economics" can be so different. It's a box with some machines in it.