We attended the Rally in March in Phoenix. We saw quite a few 5th wheels and a limited number of bumper-pulls there. Most of the rigs were motor coaches, however. We enjoy attending the seminars and always learn more about taking care of our rig, good ideas for improving it, and meet super people (I think I go to meet the people.) This was our second Rally.
Our first rally we bought things like surge protector for the rig, tire monitors, and some minor things to make life in an rv more rewarding. I think the earlier post about less competition may be correct...either competition figures the exposure is not worthwhile in the Camping World camp or else they are not allowed/invited...not sure.
Still the entertainment is always excellent and I always learn something very worthwhile (gem of the 2012 Rally was Solar Panels and dry camping). And the people...we always stay off-site, so we don't meet as many as others, but still very nice.