Re: CLI strikes again...
That's certainly true, if a parsing flaw is present. But if the parsing component is flawless, and rigidly so, then it's robust and won't let mistakes propagate. Dbus uses a schema driven code generator, I'm assuming with the need for interface parsing rigour in mind (though it lacks value constraints).
It basically comes down to what's better, getting a single parser generator correct or there being a myriad different ways individual devs and libraries go about parsing. It's probably more efficient to focus on the single parser generator (per language).