Agile is best practices around iterative and incremental development. That's it. It's a marketing term. Of course most of this stuff has been around forever. Most folks who "get" Agile say something like "This rocks! It's like we used to do things when we had a lot of fun and kicked out a shitload of code."
From observing teams the interesting thing is how many people used these techniques back in the day, stopped using them over time, and then don't want to go back because it's something "new". People are strange.
You should attend one of my classes. I ask what Agile is and then tell everybody it has no meaning at all. It's just a big blanket term we use to re-wrap a lot of that older stuff (and some new stuff too).
In my opinion the biggest problem Agile has comes from the people who like it. Skeptics are fine. I can show you this stuff works. But people who did "Agile" one time and become cheerleaders and set in their ways can be insufferable.
From observing teams the interesting thing is how many people used these techniques back in the day, stopped using them over time, and then don't want to go back because it's something "new". People are strange.