Congress passed the ADA in 1990. There isn't much more they can do - they have limited power. (there were a few updates since then, and I'm sure there are more tweaks they can make, but the majority of their work is done). Most of the authors rant are not things the government does or should do, government buildings generally are ADA compliant these days. The rant is about non-government things.

The biggest thing that I want is a way for ADA to realistically apply to invisible disabilities like autism. Although in theory people with invisible disabilities can get accomodations, in practice the accomodation that they really need is "stop being a shitty employer".