HTML was that way! "Hey, look, it's a spec where any computer can send a request, and you get a nice, structured text document back that's machine-parseable. It even words for the blind, who can just plug their own preferred reader into the doc! Problem solved."

Oh wait, except most of the audience isn't blind, and starts using clients that can do ever-zanier things with the UI. Designers want to appeal to this market. The beautiful, parseable structure of HTML gets forgotten about, and it's no longer usable by the blind.

So you want content providers to support an api endpoint that works like HTML used to? Okay, but what stops that exact process from happening all over again?

Or, maybe you mean that every provider in existence will support two versions of every endpoint: the meth-addled zany design, and the standards-compliant, usable one. Okay, that could work, but it seems a lot harder than just having one version that makes a small effort to make itself more machine parseable.