I've been working in games for 10 years, and I really, *really* wish I could agree with you.
Did you know that it's only been in the last few years that review scores and sales started to correlate? Until recently, there was virtually no connection between the review scores of your game and how well it sold, and it's still somewhat tenuous.
(see http://games.venturebeat.com/2009/05/29/does-game-quality-translate-into-better-financial-performance/ and http://www.dreamdawn.com/sh/features/sales_vs_score.php for some backup on that.)
If I could show you a graph of marketing budget vs sales, you'd see that the correlation is much stronger. Making a great game doesn't immediately make people aware of it, and the public isn't the most sophisticated video game consumer.
Remember Daikatana? (http://en.wikipedia.org/wiki/Daikatana (I can't believe I'm posting a wp link in case people on Slashdot don't know what Daikatana is. No one click that.)) It was famous for being over-hyped and a total mess. It looked good once, but by launch anyone who knew about games knew that it would not be good. And it was still a top-10 seller for 3 months on the back of name recognition. Because the majority of game buyers don't know much about games (just like most industries). People had heard of the game, and they forgot that what they heard was a joke, so they bought it. Oh yeah, it had a big marketing budget too...
The reality is, sales (and therefore income) are better correlated to investment in advertising than the game itself. That pains me (as a game designer) deeply, but it's true. Things like this article used to peg my rage meter, but there's no point in getting upset at EA for realizing the way the market works.
Luckily, that's changing. The market is becoming more savvy, and quality is finally becoming important to publishers. I'm not spilling inside secrets when I say that WB is very excited about the high quality of Arkham Asylum. They knew it would be good, but you can never be sure that a game will be great, and their faces light up whenever they talk about it. It's very encouraging to me to see executives this excited about quality; that's new.
It's now common to hear people say things like "They're an 80+ developer" or "We're targetting 85+", which is also really encouraging. People used to talk about making good games, but now it's important that you be able to clearly establish that. It used to be only sales that mattered, but now people are more willing to accept that if you make quality games, the sales will come. That's huge, and you can expect to see it shift more resources from marketing to production, where they belong.