Melkor, the thing you have to realize though is that D&D is played by more than just groups who have been playing together for years and have internalized a social contract that makes everyone happy simply by virtue of the fact that they've played together for years.
There are far, far more groups out there for whom membership is a matter of months (if not weeks). School groups, whether high school or uni, tend to fall into this category IME, where people's lifestyles are so in flux that the idea of having a stable group for years on end is rarely achievable.
Then there is also organized play which plays a very large part in WOTC's business model. In Organized Play, you don't have any of the qualities that you are speaking of because everyone at the table is a stranger and will likely never see each other again.
You're absolutely right in that play experiences will color perception. Totally agree. When I polled this topic a few years back, about 1/3 of people claimed that their overall experience with DM's was poor. So, you get into the
Gnome Effect where, while it's never the majority, because poor DM's are very common, generally any new(ish) group will have at least one player who's been totally burned before and is not exactly jumping up and down with love for his new DM.
You are absolutely right in that there are very, very few problems in a game that a group, as a group, cannot solve. That's absolutely true. Heck, 1e play was virtually predicated on the idea that the group will take the rules and fold, spindle and maul them into a shape that the group wanted to play.
I don't think games are given that amount of latitude anymore though. We've seen the lights of Paris and we generally can recognize good game design from poor (even if it's only good or bad from our own point of view). And people are a lot less willing, I think, to simply shrug and start playing amateur game designer. We did that and, for a lot of us, it resulted in many, many hours of piss poor games.
Heck, look at the HUGE amount of criticism WOTC gets for errata for 4e. If you were right and problems can simply be solved by DM's applying common sense, then why are so many people so up in arms that WOTC has errata for its books? After all, it should be a simple matter to fix the game yourself. Why berate WOTC time and time again for improper play testing or releasing rules too early or the like?
The answer is pretty simple. People (rightfully so) expect games to be at a certain level of professional design and when the game in question fails to meet that standard, it's heavily criticized. If 1e were released brand new today, it would get absolutely shredded by gamers. It's a different community in 2012 where we have had decades and hundreds of thousands of hours of play time to educate gamers on game design.