It all comes down to what do you get for your money. At that point you can attach a value to it. When I was playing WoW hardcore, it was literally the only game I needed, as such at a mere £9 a month it was an absolute bargain to me. Normally I would have spent minimum £3 a week on rentals and probably bought at least one new game at £30-40 a month, so we're talking £50+ a month pre-WoW.

Then WoW came along, it is to this day simply the greatest gaming experience of my life, bar none. I played not for hours, or days, or even weeks, but literally months of game time over almost 5 years. I needed no other game, I saved a fortune, and I had so so so much fun.

So was it worth £9 a month, definately. If someone doesn't play it a lot and still buys many other games, I can see your argument, but if someone plays like I did, then the argument is moot.