People are finally starting to admit that XML is harder than it should be! Tim Bray, the creator of XML, himself even says so. In my view, XML has two advantages: 1) it’s structured and 2) it’s becoming accepted by the masses.
And #2 is the most important one. We’ve had comma/tab-separated files that were simpler and, egads, actually worked, but there was no hype surrounding it. So now we have XML being marketed to all the dopey programmers of the world (to sell them XML tools, of course), so it’ll probably catch on and stick. I remember a couple years ago somebody at an unnamed company asked me if Recipezaar uses XML and he was happy when I said it does. He didn’t even know what that meant and didn’t care how we used it or what the DTDs we used were, but the magic letters X, M & L were meaningful to him. That’s when I knew XML was gonna be big.