Yes, it's clear that Rails blazed the path for Merb. At the same time, the Rails people really shouldn't be surprised (or feel badly) that their "opinionated software" has created a market for flexible, agnostic software.
Both projects are great, and will probably appeal to different sets of developers. In a lot of ways I think of it like the dynamic between Python and Ruby. Both are excellent languages with very similar capabilities, yet they appeal to different developers. It's like there's an element of personality in there, and there's nothing wrong with that.
And for the same reason, I use Django everyday, but I ♡ Rails. Rails, Django (and Merb, Ramaze)are not fighting each other for mindshare, but Struts and company.
I will cautiously agree with that - cautiously because I don't want to become a part of it exacerbating the problem.
To everybody wondering why there is such an echo chamber in the rails and (increasingly) merb communities: consultants. They all try to build a profile online to get better paid gigs (and to boost their egos).
Resorting to the rules of (self-)promotion, these consultants write link-bait, (fake) flames/controversies, etc. They give noobs and hype sheep the warm feeling of "being part of something big" and enterprisey folks can point to the "wide adoption" and "active communities" around them. That does not make them great or better than other solutions technologically. (As an aside, they're still very good web dev tools, no doubt, but not the second coming of <deity of choice's son>).
Both projects are great, and will probably appeal to different sets of developers. In a lot of ways I think of it like the dynamic between Python and Ruby. Both are excellent languages with very similar capabilities, yet they appeal to different developers. It's like there's an element of personality in there, and there's nothing wrong with that.