There's a lot of selection bias wrt who submits posts to HN and the types of content they submit. It creates a sort of perception that tech/libraries/languages are moving near the speed of light and anyone who isn't treading along the bleeding edge is obsolete.

As someone who doesn't write Ruby, even I can grok RoR in a few hours. And even though it's boring and not trendy, it gets the job done for a lot of use cases.