@bldssphq A few things from my experience managing affiliates. Yeah, 90 minutes would be great for those that want it. Most people don't want to make the 90 min commitment. You're arguments are compelling indeed, but that adds a lot more time to a class. 11 years managing affiliates, the most common reason people quit or leave is because of class not working in their schedule. Again, the vast majority are fine with 60 min.
There's also a business component. Most gyms are small and can't get the same amount of people through in a given time. They simply dont have the space to add more people to a longer class. Lastly, to the point before, the busies time it all gyms is before and after work. There is some logistical issue with having classes that last 90 minutes for people to make it work. 60 minutes is the sweet spot.
I have also seen a trend in 40 minute classes. Basically gyms running classes that offer a CrossFit class that always has a shorter workout. Not going to cast any judgement on whether or not that is a good idea, just that it is happening.
Probably the worst trend, in my opinion, happening at CrossFit gyms is the "no after class" structure. Gyms eliminating work outside of class. Whether its a 40, 60 or 90 minute class, gym's should be allowing people to get that extra work in. My two cents.