Learn Technology Y
She’s right, you know. But I think a better way to put this is to not learn a specific technology, but learn how the technology works. Learn the fundamentals, and when the landscape shifts, you may have a bit of catching up to do, but you won’t be starting from scratch. You’ll understand some of the decisions that were made in the design of technology Y, and if you’re early enough in the process, you might even be able to shape it to fix some of the pain points you’ve felt.
Yes, I agree, understand things conceptually. Then all that’s left is to deal with people hiring that do not understand concepts and are wondering why you are not explicitly stating something, to which you counter by casually sprinkling words on resume :(