For the most part, few if any vacuum cleaner manufacturers are still in the business of making their own motors. They are generally outsourced to a third party company, each of whom offer a vast selection of models with varying specifications. It will be they who redesign motors to suit the upcoming legislation, with vacuum manufacturers continuing to simply buy them "off the shelf" as they always have done before. This may mean they end up paying a few extra pounds for each motor, which will undoubtedly be passed along to the consumer somewhere along the line, but the vacuum manufacturers themselves will not necessarily have to sink millions into R&D as far as motor technology is concerned. All they need do is ask their supplier to provide a motor that uses X number of watts and gives Y amount of suction, wait for them to arrive and then start slapping them into cleaners on their assembly lines.
Something tells me Numatic may have been working alongside their motor supplier to come up with a particular specification for their upcoming models, and have it ready for market at such an early stage, hence their large spend on this project. I cannot see the price of a Henry going up however, because the £100-ish price point (give or take a tenner) is so firmly established now. They are far more likely IMHO to recoup the R&D costs by tacking an extra quid or two onto other products they sell, or trimming costs elsewhere.
Dyson will most likely continue further down the digital motor route. The more this ends up costing the better as far as they are concerned; it serves as fodder for the gadget blogs, which in turn boost sales amongst those who simply must have the latest and greatest "technology". Whether or not it actually keeps the house any cleaner is besides the point, but then it always was. If you think their £430 upright and £460 cylinder are expensive already, wait til they stick a digital motor in them. It will be just the push needed to break through the £500 price ceiling.