When you claim to be a senior engineer with 20 years of experience and you don't know what ES6 is then you don't deserve a job.
This is what's really wrong with software engineering: we have young, cocky and mostly ignorant people doing the hiring. From CEO's riding daddy's coat-tails while trying to pretend to run a company, all the way to college grads that think their training as a flaming-hoop jumper is the pinnacle of engineering.
You do this to yourselves.
Some of us do other things, you know.
I think that the main solution to all of this is that you need to have skills with a long shelf life in addition to being up to speed on what's hot right now.
Bringing up a new release of a language as being essential for any programmer is missing the point here.