In my opinion, John Bolton once again, hit the nail on the head.
We used to offer a revolving Power Wand (18" nozzle x 2000 rpm's) for years--since discontinued because of its' unpopularity. The Professional Cleaners would inform us that it did great (better then a rx 20/roto vac) on commercial short nap carpets but not as well on longer nap, shag style carpets (as a rx 20/roto vac would).
So, there seemed to be a trade off here. However, it was a valuable tool to have in ones' Tool Box for certain applications.
When operating these style Power Wands "efficiently", I also believe that it requires at least 2-3 stages and really, much greater psi; ex: 200 psi, but no more.
Good Fortune to Small business;
Ed Valentine
cross-american corp.