[hga]

Does "keep up" require experience that can be cited on a resume?

"Experience in relevant technologies trumps almost everything else."

Hmmm, in my experience, unless it involves a big paradigm shift, such as moving to OO or functional programming, new "relevant technologies" can be quickly learned on the job, unlike being able to design systems, write good code, debug quickly if that's possible, build and debug systems, etc. The sort of stuff that takes more than a few years to learn how to do well.