Why are we so productive with Rails?

Paul Butcher wrote:

82ask.com

"On the back of this experience (and after a lot of internal debate!) we decided to rewrite one of our existing PHP systems in Ruby on Rails in June 2006. Including load testing, end-user trials etc, it took three developers six weeks to entirely duplicate a 22,000 line PHP system with approximately 5 man-years of work invested in it. The final Rails system consisted of 6,000 lines of code."

Luv them rewrites. Could you have rewritten in PhP and achieved fewer lines? Of course! But an order of magnitude fewer? That's the definition of a Silver Bullet - an order of magnitude in one rewrite...

DRY, soft typing, wall-to-wall unit tests, browser-safe JavaScript, and instant Domain Specific Languages for everything - what more do we need?