Frankly I think you're giving Hoover more credit than they are due, HiLO. Dyson certainly knocked the wind out of Hoover Europe's sails, as with every other brand.
Also Candy took Hoover Europe over in 1995 and to be honest with you, I don't think the home owner company had much to do with an improvement of whatever - to Candy, Hoover's existing larger home appliances like freezers, washers and dishwashers meant Candy could double their sales with their own machines as well as Hoover's own larger line up.
I don't think Hoover were that bothered with The One until the media and consumers complained. It wasn't until problems started to surface (and probably helped by the damming report from Which?) that they made some kind of effort to improve the original One design, but as Steve says, any of the changes didn't really help the majority of the problems that the original design had. After all, bad news is never good news and Hoover were caught out for not properly testing the One thoroughly enough, hence a recall/newer changes had to be implemented.
Suggesting that Hoover were going down the pan "for the previous 10 years or so," isn't fair to be honest - when you consider that Hoover were still producing and selling the bagged Turbopower 3 as far as 1997/8, those bagged uprights weren't half bad. Infact quite a few models were good - so much better than the Purepower.
Then when the Vortex arrived and caused Dyson to take Hoover to court, Hoover then spun out the design with many other different models, essentially similar with colour changes and name changes such as "Hurricane," "Cyclean," "Whirlwind," and of course the "Vortex" with a big foot version - timeline wise - those Purepower BASED upright models were all released BEFORE The One was produced.
I had a Cyclean for a while - nice colour but ever so bulky to use and mine came with plastic poly dust bags, which was weird given that it was supposed to be a bagless upright. See old link from Vacuumland.
http://www.vacuumland.org/cgi-bin/TD/TD-VIEWTHREAD.cgi?6603
Also link added here of the existing Hoover Service "problem page" for The One. Click on the "cuts out/blocks" problem and see how many filters they suggest that need clearing!
http://service.hoover.co.uk/advice-...gless-upright-vacuum/troubleshooting/the-one/