I thought it was odd that JemyM made the comparison to begin with, but I certainly wouldn't consider Halo a "console-centric action game" just because it was developed for the X-box first. What exactly makes it console-centric? If it had been released for PC first nobody would have known the difference. The age-old "just because it sold more doesn't mean it's better routine" isn't lost on me, I don't automatically think something is great just because it sold 10 Million copies. On the the other hand, it's just as naive to dismiss sales as being meaningless when they're obviously not. Hype alone does not sell games, if that were the case then Daikatana would have sold 10 million copies.
Sales aren't meaningless, they simply don't reflect quality.
Daikatana might not have been a big seller, but it sold around 200.000 copies, which wasn't that bad considering the time of release and the utterly devastating reviews it received. In my opinion, that speaks directly against your claim that they mean something in terms of quality. If a game that universally despised - which cost so much to make - can cover production costs, then there's simply something wrong now isn't there. Yeah, it's hype.
Halo was - at best - a mediocre shooter. I completed it on the PC out of sheer tenacity, and thankfully it wasn't long. The story was great? You've got to be kidding me. The level design was horrible and the gameplay was extremely single-minded and overly simplified. It wasn't bad overall, which is the reason I managed to get to the end, but it's definitely one of the worst shooters I've bothered to complete, and I've completed MANY of them.
Judging from professional reviews, Halo 3 was more or less the best modern game in the world until GTA4 - which is about the biggest joke I can imagine. It's all about Microsoft funding the marketing campaign and the media happily providing a service in terms of overly favorable reviews.
The entire industry is saturated with corruption and compromise, and why wouldn't it be? It's all about money, and EXACTLY the same has been going on in Hollywood for decades.