Perhaps he doesn't... but I think Sir Vincent is right to question your assertion anyway.
It was never an assertion. Look at my original post:
Apparently, for all its merits, the Viking line didn't sell too well
I said 'apparently', to make sure people knew I wasn't stating it as an outright fact, it was just something that I thought could be true. However Sir Vincent didn't include this word when he quoted me, so it now looks like I am asserting something when I wasn't, at all.
Anyway, whilst I can't offer any official evidence that the Viking line didn't sell that well, there was one old post by Chrislad77 that offers a possible explanation:
Being in the Lego store alot, and knowing employes it seems to me that the Viking line was not very sucessful. People like minifigures, and the viking sets weren't exactly short of them but I think the technic stuff turned off parents and kids alike. If you want technic you tend to buy it in a Technic set, no body is interested in a brick/technic mix. The lack of an enemy hurt the brand. Customers who want a medieval era set, want a castle , they want to bulid castle-ish things, I don't think TLG did a good job of presenting the Vikings as appealing.