^^^ Yes, there's a lot of truth to that. You'll see in sicily all the kids are speaking proper italian now, and moving away from the dialect. Maybe just in the homes or whatever, they speak dialect and the older ones will always speak dialect, but parents are speaking more and more italian than sicilian today. That's true. But try and convince a sicilian they are "all one" and good luck to you.
If someone in the US asks my husband where he's from, due to his accent, he answers "Italy." If they say "what part?", he will then answer "sicily".
edit: this post was in answer to your next to last one.
I agree again. Most Italians don't feel united YET. But years from now I'm sure they will. And that's the way my relatives used to answer. They'd say they're italian and then if they were asked what type they would say sicilian.
