Several points in your post are worth commenting on. James Dyson is an engineer, and he likes to champion engineering, as he struggled to get innovative ideas taken up by establshed companies. Dyson employs huge numbers of ‘engineers’. I know this as an ex-colleague, an Iranian with a PhD, went to work for them. They have a lot of PhD level staff. They design their own motors for example.

And as for your comment that Dyson changes the rules to sut him, in fact the rules had been stitched up to favour hoovers with bags. As for how good Dyson vacuums are, countless independent reviews conclude that they are the best. That said, the latest Bosch vacuums do look good.