I disagree. It sounds like you work for a company who has their build process worked out really well, so fast changes are less impressive to you, but have you considered that maybe your company is not the average? I think it would be fair to say that most development shops are NOT that responsive to user changes because they don't have either the language features pg used, or a well-thought-out build process like your company.
If the article author works at one of those "average" shops, I think he has every reason to consider his experience on news.yc as a breath of fresh air and tell other people about it as an example.
Additionally, I think part of what impressed the author so much was that pg took the time to handle the request immediately. This isn't a site anyone pays to use, there's no revenue incentive, and the request was not the early stage of a riot, but they took care of it as though it was as important as a paying customer relationship, and that's not a response you expect from most web services. In fact, I think that may be what impressed the author more than just the speed of the fix.
I should have known the magic here would be completely missed by much of the Hacker News audience - same thing happened with the comments on my blog. The whole point was that it WASN'T about the technology - it was that he's so in touch with his audience that within 4 hours of it coming to his attention, he was able to do two iterations, get feedback on both, and fix a bug. It took 4 hours because we were communicating asynchronously on a message board, but I'm pretty sure he could have done it live if I had him on the phone. Simply put, I was more impressed that he gave a crap than that he could push a code change.
I am at one of those "average" shops, as are most people (by definition, although maybe not in the HN community). I know this stuff is possible but we can't do it here, and neither can most sites.
To put it in perspective, if you found a bug in your bank's website and told them about it, how long would it take for them to fix it? Even worse, what if you suggested a way to make the site work better? Would anyone with decision making power ever even see the suggestion? Just try telling someone WHO'S NOT A GEEK this story and see what they say. I wrote the article because when I told my wife what happened, her jaw hit the floor.
We are consultants here in Bangalore and we have routinely done this on a Python/Django social networking web app and a Ruby on Rails web app. code-test-svn commit - svn export , pretty much.
With a lot of java experience, I can say that it is more elaborate and laborious in Java than python or ruby. The erlang movie (http://video.google.com/videoplay?docid=-5830318882717959520) shows off the same, for erlang.