I reckon Dyson's comment is merely to conceal the real reason: young engineers are cheap.
There are plenty of them, they are easily manipulated into working long hours.
They are disposable (and "Not taking notice of experts" means your operation will soon go broke: reinventing every wheel that the experienced guys in the neighbouring companies just take, off the shelf).
I doubt that if Dyson had shareholders to worry about, he would take this view. But since the company is his own personal play-thing, he's welcome to spend his money as he pleases. But so far as products go, his company seems to have a problem learning from experience. Nobody I know who bought a "die-soon" vacuum cleaner would ever buy another Dyson product.