I don't have links right now but Valve has published some numbers that seem to suggest the opposite- that their low price sales sell so many more copies of games that they bring in more revenue than when the game is at full price.
Also you can see how effective the model is for indie games. Take Stardew Valley for instance. A hugely successful indie game that's made the author a ton of money. And it still sells for less than Harvest Moon/Story of Seasons.
Isn't this the parents point? There super low sales drive prices down because they work. Personally I see this as 'the market' working in a helpful way for consumers and don't see the problem with low price expectations. Not like the rate people are making games to sell is low.
The thing to keep in mind is that this is the Wal-Mart model: drive prices as low as possible (and maybe sell in bulk). It squeezes/kills the little suppliers (such as indie developers), drives down the notional market value of goods, but feels like a good deal for consumers.
At least in current society there isn't anything overtly wrong with "the Wal-Mart model" as it stands, but recognizing a Wal-Mart model is the first steps towards trying to figure out if it is long term healthy for the community. (Which brings us back to the article at hand, questioning the long term health of the community in the face of a Wal-Mart like Steam.)
Indie developers complain about Steam because they are the most vulnerable to its problems. They don't have the pricing power to avoid the race to the bottom of sales. But without Steam and the distribution it provides a lot of them wouldn't have a business model.
So on one hand: Isn't it great that there is this easy way for almost anyone to distribute their game; and on the other: isn't it terrible that so many people are distributing their game and driving down the price?