Again, in principle I don't disagree with your point. The danger is in the reverse - someone hired because they know tech 2013X, but don't really know how to do anything else with it, nor how to problem solve. At the same time, someone with 20 years of experience who perhaps just finished up working with tech from 2010, because that's what that client/company was using, and gets ignored as "not modern".

But your bigger point - yes - have modern skills, and being able to show those with relatively current tech is the best way to go. Personally, I'd take someone who is older but within a few years of current tech vs less experiences with only modern tech. 8 years of Java and Ruby with experience up to Rails 3 vs 1 year of Rails 4 only? Should be a no brainer for most situations, unless the job is "writing Rails 4 tutorials" ;)

There's a huge spectrum of middle ground there, and good companies/recruiters should be able to divine that. ("should" being the operative word).