The logic's broken because you looked for an example that supports your point of view, then used it to support that point of view (circular argument)! Of course powertools.co.uk hasn't sold, but that's true because you looked around until you found an example of a domain name that's still held by a domainer...
It says nothing about any other generic domain name, nor about their attractiveness to end-users.
Of course power tools hasn't sold?
But it's a generic Edwin!
It's not broken logic, you can apply the same logic to thousands of other companies, that was literally the first one that came into my head.
I'm sure if people spent 5 minutes thinking they could come up with oodles more - how about Dyson, Hoover, and all of the vacuum cleaner manufactuers.
Hoover etc have had decades to work out what works best in terms of advertising, and have any of them bought vacuumcleaners.co.uk?
What about Ford, Nissan, VW, etc - do they feel the need to own cars.co.uk?
The list is almost endless.
And as for finding an example that matches your argument - you're a guy who has a couple of thousand generics, and you're trying to play down the relevance of hyphenated versions.
"Man who's registered thousands of EMDs in "hyphenated domains are worthless" shocker!"