I think you're right about a lot of things. Things like Backbone (which I wrote about at http://blog.appfog.com/putting-some-mvc-meat-into-your-app-b...) will make recourse to the back end more and more selective as time goes by. JavaScript is indeed quite a force, and as far as I can tell that will stop only when browsers start reading other languages directly (which is not completely unthinkable, but also not really on the horizon).

My point was not directed so much against JavaScript as against the notion that PHP is simply an anachronism.

There's also nothing stopping you from using lots and lots of front-end JavaScript in a PHP-driven context...