Funny thing about the state of modern vacuums - it seems peoples' expectations of what a vacuum will do have changed too.
As a case in point - my mother hires a maid, but the maid uses my mother's vacuum. Since she's been using this maid (until recently) she had a Dyson DC24, which did a pretty good job on the loose shag carpet in most of the house, but not on a much denser, deep-pile large area rug. On that, it just didn't get the pet hair off. The maid thought nothing of this - "Oh, when you get long dog hair on a rug like that, it doesn't come off without a lot of work," she'd say. And then the Dyson croaked, and got replaced with a Royal 996. Next time the maid came to clean, she was *utterly* floored that the Royal got all the hair off in a single pass. She made quite a fuss over it, flabbergasted that "this ancient vacuum" could do that, when she'd never seen a modern one that could. (Obviously she's never used a Simplicity, a Miele with a full-size PN, or even a Panasonic PN canister, but that's another story!)
My brother had a similar experience with his Bissel upright not removing cat hair from an oriental rug, and thinking that's just how it goes, too. (A roommate's mother brought over a Sebo D4 and showed him that it was possible, though!)
There's also a lesson in matching your vacuum to the surfaces you have to clean - but most people wouldn't know that, since most vacuum marketing materials don't mention it. I'd expect that Dyson would, since of all of them, they seem to have some of the pickiest brush roll designs of anybody, but hey...