It's more like "Everyone is talking less about Rails" - the only new kid in Rails block is Haml/Sass and Rails is obviously stagnating compared to the hype it had couple or more years ago. Ruby/RoR is more about evolution now: Rubinius, JRuby going for stability, SalesForce adopts Heroku as one of it's development platforms - look, even one of Big 4(DTT) hires RoR-consultants now.

JavaScript on the other hand is booming both on client (SproutCore, Backbone, Cappuccino, CoffeeScript, GWT) and on server (Node). JS is just more "hackish" today - browsers are evolving day-by-day, taking more and more functionality from server - RoR isn't key to success anymore, it has become just another alternative for your REST backend.