alt Hacker NewsThat doesn't match my memory, though its been a while now!
I remember the arguments largely revolving around verbosity and the prevalence of JSON use in browsers.
That doesn't mean bandwidth wasn't a consideration, but I mostly remember hearing devs complain about how verbose or difficult to work with XML was.
Your memory is correct. Once compression was applied, the size on the wire was mostly a wash. Parsing costs were often greater but that's at the endpoints.