That 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.

But one of those endpoints is a client on a mobile phone, which when we started with Internet on mobile devices wasn't a particularly powerful CPU architecture.

OK, but XML is a pretty solid format for a lot of other stuff that doesn't necessarily need network transmission.

This is true, but if other formats work for those purposes and also network transmission, they'll start to edge out the alternative of supporting two different protocols in your stack.

if bandwidth was a concern, JSON was a poor solution. XML compresses nicely and efficiently. Yes it can be verbose to the human eyes, but I don't know if bandwidth is the reason it's not used more often.

JSON absolutely isn't perfect, but it's a spec that you can explain in ~5 minutes, mirrors common PL syntax for Dict/Array, and is pretty much superior to XML in every way.

Sure, but the argument is bandwidth which is what I’m comparing them to solutions to each other against.

The article addresses this.