The sad thing is that it was abused, horribly, in the early naughts when people tried to take it too far. On the one hand it was rushed out without the proper tooling and you had humans typing raw xml without the right amount of support from intelligent autocomplete coming from schema-aware editors. On the other, you had systems that tried to force XML into roles that are better suited for a programming language (I'm looking at you, ANT). And worst of all, it became the centerpiece of a bunch of tech that people really hated-- remember all that crazy WS-* shit, and "SOAP" (which could have stood for "Complex Object Access Protocol". All this wasn't the "fault" of XML which, IMHO, has rock-solid core concepts. XML got an undeserved bad rep from association to the failure of the things it was used with.

XML still survives, though. The tooling is good. If you type XAML or HTML in the right editors, it's serves the purpose competently and without drama. People aren't going crazy finding new XML based applications anymore. It's just doing it's job. I prefer pure XML for config files even now-- of course I never expect users to see it or type it. XML, at the end of the day, is intended to be manipulated by tools.

I wish I could say the same for yaml and to some extent json. I feel like these things are about to be abused like XML was.