Early web technologies like CGI, PHP, JSP, ColdFusion, ASP and ASP.NET arose due to real-world needs.
Ruby on Rails, on the other hand, arose mainly due to hype.
From a technological perspective, there really wasn't anything special about Ruby on Rails. Many of us who had been doing web development for some time had already built or used proprietary/in-house frameworks that offered the same functionality, but were written in Perl, Python or Tcl instead.
If it weren't for strong and very loud personalities within the Ruby on Rails community, combined with some very lucky timing with respect to the rise of the so-called "Web 2.0", it likely wouldn't have been seen as "special", and wouldn't have garnered the hype that it did.
Technologies that come out of an environment of hype, rather than solving real problems, tend not to stick around as long. Systems built using technologies that solve real problems continue to be used and maintained. Systems built using technology chosen purely because some manager or executive saw a webcast full of nice-sounding buzzwords tend not to survive very long.