My late father was a nightclub singer. He used to say, "People don't clap for music they like, they clap for music they RECOGNIZE".
This is the reason why every high street in England looks the same. It's why people visit Manhattan and eat at Red Lobster instead of one of the dozens of fab and unique restaurants just a few blocks away. No excuse these days, what with the ubiquitous TripAdvising-type sites.
At WDW part of it is cost-related, too. A family of four is going to be dropping $100 for dinner (at least). "Well, we know what we'll get at Rainforest...It's OK...nuggets for the kids. I don't want to risk spending all that money on something weird that I might not like...".
I get both sides of this. I love ethnic food and I prefer unique, family-owned places...but I also eat at McDonald's IN FRANCE* (and so do thousands of French people, every day).
As for Kouzzina, I'm disappointed. I love Greek food and was excited to try it this autumn (when DH, who HATES Greek food, will be staying at home).
*This is due to the extremely disobliging restaurant opening hours in France. They WILL insist on giving their staff adequate time off...
...whereas Mac and Don's Supper Club is open all
jour long.