Because nobody cares about suspend-resume power mgmt. If it doesn't work, curse it, pull it out and put it back in again, voila it works.

The people who really care about and study the spec, are those who have to support fixed devices i.e. USB devices internal to an appliance. They physically cannot be removed by the user. So suspend/resume has to work.

Embedded programmers have to deal with totally-broken drivers/specs all the time. There are probably 100s of folks who knew about this and dealt with it (bumped the timeout in their embedded kernel to match the devices they support) and never said anything to anybody.