The problem with XML was that people tried to make it semantic. You had XML Schema (awful), and because of schema you had to have namespacing (also awful).
Take that away - plain unnamespaced tags, with no semantics beyond "this is a character sequence", common-sense business-specific tag names, and no schema - and you get something that's just as nice to work with as JSON is. And there are plenty of libraries (e.g. Jackson) that will serialize back and forth to objects. But too many people drank the semantic kool-aid and tried to autogenerate classes from schemata or other such silliness.
Take that away - plain unnamespaced tags, with no semantics beyond "this is a character sequence", common-sense business-specific tag names, and no schema - and you get something that's just as nice to work with as JSON is. And there are plenty of libraries (e.g. Jackson) that will serialize back and forth to objects. But too many people drank the semantic kool-aid and tried to autogenerate classes from schemata or other such silliness.