Earlier quoted context omitted.
As a web user, I'm not grateful. I don't think having more pixel-perfect control or slightly faster JavaScript makes the web any better. All websites look slightly better, but the client side dies a little bit every time. In the web circa '96, anyone could write a web spider or web browser, and everyone did. There was tremendous innovation both client-side and server-side. Client-side innovations included things like…
With the hyper-AJAXed world, client-side innovation becomes impossible. What?
At the time, we were talking about developing all sorts of agents. Things that would shop for you. Things that would find parts for you. Thinks that would remember what web sites you visited, and let you search them. Things that would track where in a long set of pages you were (blog, comic, etc.), and let you keep reading from there. It happened for a while, and then it died when the web became too damn hard. Writing anything that can reasonably see and parse web pages now takes many, many web years. There are only four or five organizations with that kind of resources (WebKit, Mozilla, Opera, IE, and internally, Google). There are countless things we just didn't even imagine.
It's like the DMCA. You notice all the innovations that happen, but you miss all the innovations it made impossible.