Back when NAC A4 was released it was considered absurdly expensive. IIRC it was at least 3 times the cost of QED 79 strand which was just about the only other 'audiophile' speaker cable available. A5 upped the game even more costing best part of a fiver a meter. By supporting active drive and minimum lengths Naim wanted to sell the end user quite a lot of the stuff too. The big thick burndy leads have always been expensive too, though as with most Naim interconnect leads, are absorbed into the asking price of the component. I'd argue that Naim actually drove the expensive cable market; they were there right from the very start. The only thing that has changed is that they have been eclipsed by purveyors of even more expensive bits of wire and the market has adapted and now accepts 'audiophile' pricing.
Tony.