Or, maybe if we collectively push for a culture where employers who expect you to learn new technology pay you to learn said new technology, staying up to date won't feel so awfully one-sided.

Why would they do that when there are people there is a large enough supply of people with the relevant skills?

I'm sorry but even if you know the ins and outs of language or a framework, it still doesn't matter if you do poorly on white board questions. As much as everyone says "its to see your thinking process". Nothing you've worked on in the past or have experienced matters.