I think this is true. Part of the fun of Ruby a few years ago was "sneaking it in" in a particular environment and having people wonder where you found the time to develop all of these new utilities you were using.
What I find fun about ruby is that, for better or worse, the language makes it convenient to express programs in a way that is very close to how I naturally think about them. Also: it's got pretty good libraries and a good community.
I would've found this blog post worth reading if the author would've explained why the shift from upstart to accepted technology means that for people like him ruby is no longer fun.