Also, those technologies probably don't scale at all to 1000s of servers, something a Google project has to do from day 1.
(I'm not sure they'd even be fast enough on a single server. As a rule of thumb, the more technologies you put in the mix, the more abstractions there are, the harder it is to minimize the work done.)
The earlier you launch, the sooner you need to do that scaling work. But the later you launch the more development you do in a vacuum, without real customer validation.
CoffeeScript and Backbone.js have nothing to do with scale, as they are used on the front end.
The author talked about how horrible it was to have the UI written in Java (having to wait 3 minutes for a recompile after a CSS change). These two tools (plus SASS and alternatives) on the front end makes Java->Javascript totally redundant, imho.