Absolutely. Whenever I see a new project, I look at business risk and technology risk. Either one is OK, but both are not. (I picked that up from someone, don't remember who).
I think that there's real value to being a Tom Bombadill (and really learning a language/framework/problem space deeply) as opposed to being a Gandalf. However, one fundamental issue is it's easier be a consultant and speaker if you are focused on the new shiny objects, and so much of what is written is from that perspective.
Perhaps it depends much on the mind of the person; I don't think I could just focus on one thing forever. But while the new shiny tech guys may seem to have more opportunities, I believe the domain experts may get paid more and have more of their career time spent as "recognized leaders".
It's probably good that people are all different, and both types (and all in between) exist.
To analogize, if you are a general carpenter, you can always find work, but it will be at a lower rate. However, it will be varied.
If you are a fine cabinet carpenter, your work will likely be more focused, possibly more repetitive, more lucrative, and harder to find (you'll have to seek out the folks who need really really nice cabinets).
Considering that a lot of code that gets written is thrown away or otherwise doesn't survive for years, a bit of risky experimentation isn't actually as risky as it seems.
Even though I'm one of the never-satisfied/always-seeking-newer-better group (and my list of used and discarded tools/languages is very long), I do sometimes wonder if we would be better off with fewer choices and more effort spent on the concepts and methods of software development rather than on the tools.