I don't think the motivation for people doing CrossFit is worded correctly. People want to do CrossFit because it's fun. For most people, going to a normal gym is boring. I tried gyms on and off for years but could never stick to going more than 4-6 weeks at a time before losing interest. While I don't do CrossFit, I do another sport that replaces lifting, climbing in my case. I get most of the benefits of going to a gym plus it is insanely fun and I've met countless friends through it.

There is a huge market out there for fun replacements for the gym. I'm guesstimating that 75% of the people in a regular gym are not having a good time and would swap their current workout routine with something enjoyable and social. There simply aren't many choices. I can think of climbing, CrossFit, the up-and-coming parkours gyms (looks awesome: http://www.apexmovement.com/), probably boxing (although surprisingly getting punched in the face sucks), what else? In principle yoga could be on this list but in practice the yoga centers I've been to feel a bit uptight and certainly aren't social. Team sports are great fun but all I can think of are cardiovascular and don't give you any muscle building exercises.