I guess I should go further: some vacuum cleaners have to have a ground connection in the hose, to try to discharge the dust. If they removed it for unrelated reasons, they probably lowered the overall quality of the product overall.

To Shark's defense, I haven't seen too many non-commercial/consumer vacuums with grounded plugs.

That said, they (consumer vacuums) almost all have enclosures made entirely of plastic.