Maybe I come from a different background (barely-post-iron-curtain era Central Europe), but I never associated a game's intrinsic value with it's price tag. Maybe that's why I don't really understand the problem here.
As I see it, putting a game on sale months or even years after it's release does one thing: generate extra sales and interest in a game it wouldn't have gotten without it. Chances are, everyone who wanted to play the game that badly bought it on launch. Even those who were cautious and waited for reviews and gameplay footage to decide (or waited for patches after a rocky launch) and wanted it, bought the game soon after. That means everyone who was a potential buyer bought the game in the first few months after it's out. Those who didn't, either a. didn't have the money for it, or b. wasn't interested enough to buy it at all.
What a Steam Sale (for example) does, is trying to mine into these latter two categories. People with little disposable income may pick up a discounted title they couldn't have possibly afforded at full price. With the new influx of players, a good amount of new buzz is generated, which (coupled with the discount) might turn even originally uninterested people to give the title a shot. The important thing to take away from this is, that these sales wouldn't have happened without the discount. To the publishers and devs, this is basically free money they wouldn't have gotten otherwise. To the players, this is a (hopefully) good game and hours of fun they wouldn't have gotten otherwise. Win-win, right?
Also, in this new age of no demos, fake adverts and bullshots, at the "deep-sale" price buying a game is much less of a gamble. So the people who were on the fence to buy it around launch and ultimately decided against it for some reason, might try the game after all on the smaller price point. If they don't like it, it's not a painful lesson in consumerism (pre-ordered Colonial Marines? Ouch!). But if they do like it after all, they might even buy some DLC or the next installment of the game at launch. It's still a win-win!
Again, maybe it's just me, but from what I can tell, Mr. Harris says, that buying a game at anything less than $60 (or whatever it's launch price is) decreases our appreciation of said title, regardless of our enjoyment of the game itself. I honestly think that's a load of BS. If anything, a higher price point makes us enjoy the game less, because the higher the price, the less we let go and enjoy, and the more we want to desperately derive our money's worth of fun from it. And that translates straight into Buyer's Remorse [http://en.wikipedia.org/wiki/Buyer%27s_remorse] and/or Post-purchase Rationalization [http://en.wikipedia.org/wiki/Post-purchase_rationalization]. None of which is a good thing when we are talking about having fun with something.
Now, it's true what Mr. Harris said, that some people won't buy a title at full price simply because they'll wait until the "inevitable deep-sale" somewhere along the road, but there are few problems with this. First, those sales happen only after a long time after release (many months or even years). As it's been said before, those who had the disposable income and/or wanted it badly enough, already got the game from somewhere by then. These "coasters" that Mr. Harris points to are the exact two groups of people these sales are targeted at. It's a false assumption, that these sales will turn prospective buyers into "coasters". Have you ever heard "Oh boy, this awesome game I really want to play comes out today! Let's wait a year for the deep-sale so I can play it!"?. Don't think so.
All in all, I think Mr. Harris is talking nonsense and doesn't see the big picture.