It might not be a goal for Mozilla for it to be a production browser but it does seem to be for other people working on it and this is affecting what is being worked on:
I'd like to point out the significant between "browser engine" (HTML/CSS/rendering, eg WebKit) and "browser", which relies on a rendering engine but encompasses a lot more functionalities. Servo, as far as I know, is the former, presenting it as a "browser" (even if only at an experimental level) is misleading.
https://groups.google.com/d/msg/mozilla.dev.servo/-dmlVwMknJ...