While I agree a circuit board shouldn't be necessary for a task as simple as cleaning a carpet, Dyson aren't the only ones guilty of it. Even the well-respected brands, who many feel can do no wrong, are using them. Filter Queen has one under the dome, which initially came as a surprise to me given how simple in construction it is (so simple in fact, I feel they have a lot of nerve charging that much money for what is basically little more than a bucket with a motor on top). Kirby has one too, for the headlamp of all things, and if that isn't needlessly complex when a basic bulb would achieve exactly the same result, I don't know what is. Virtually every vacuum with variable power control uses a circuit board now, likewise any model that uses a cogged belt and has stall protection.
So in that respect, Dyson isn't doing anything unusual. My beef with them lies in the photo at the very top of this thread. WAY too many parts, most of which are fiddly little pieces of plastic. Not good for something that will be rammed into furniture and walls for most of its life. Older models were far simpler in their construction with significantly fewer parts, but since the ball models debuted they have taken things to the opposite extreme. Other companies merely "design" and "make" vacuums, but that simply will not do for Dyson. They have to "engineer" theirs and cram it full of "technology", because that's what most of their marketing spiel is centred on.
All this is key to breaking the £400 price ceiling, and heading towards £500 in the not too distant future. And, of course, dissuading third party repairers from servicing and refurbishing their cleaners. The original DC01 first appeared some 20 years ago and even now there are a fair number still in regular use, because keeping them running was the bread and butter of many an independent vac shop for a long time. Dyson learned a lesson there, and are not about to allow a repeat performance.
