The Ruby and Rails community is lead by individuals who are never happy with the status quo. There are always things that bugs me about development. As soon as I solve one problem, the next in line gets promoted and I work on that. I find that incredibly rewarding.
It does come with the cost of blink-and-you've-missed-the-bleeding-edge. Which I understand that not everyone has the mental bandwidth (not as a sign of intelligence, but as one of priorities) to keep up with. That's OK. You'll still be better off with just taking a snapshot of the state of the art every 9-12 months than just tuning out.
Also, you're setting up a false dichotomy between caring about the tools and the domain. The vast majority of developers I've found that can't help constantly improving their toolset is the same kind that can't help improving their understanding of their domain. In fact, one often leads to the other. I've created lots of Rails features that were directly related to a deeper understanding of the project domain, for example.