If/when agents become reliable enough, there will be no need for web apps, nor phone apps, etc. In fact, DHH got that part right: "your app should have a CLI if you want me to use it." If "English is the best programming language", then English is the best UX. I'm not navigating a silly page and filling out forms and dismissing popups if my agent can book a flight for me with a sentence and a bit of textual back and forth.

I wonder if the web will go away and the Internet will be just bot to bot traffic.

Navigating the web seems archaic in that context. Not only is that the end of Rails, but of frontend, JavaScript, etc. in the long term.