Ideally if volume demanded, you would want a tumble duster and a flatbed strap duster. Some rugs do best in the tumbler but some (tufted, some machine made, delicate, damaged or dry rotten, etc) cannot take the stress of a tumbler, thus the reason for a flatbed strap duster.
Like us, if you don't have the space, budget, or volume for both, a tumble duster is the best option. To dust rugs that can't go into the tumbler a Sanitaire or Rug Badger type duster may be needed as well.
Do the math on how much labor cost will be using a
Wolverine or Rug Badger style machine (figure roughly 10 minutes for an 8x10, 1.5 minutes/10sf generally) and see how long the pay off would be. Factor in $400-$1000 for some type of dust collecting unit and build cost for a shed to contain the tumble duster and the dust it creates.