As a busy self-learner, when is it time to learn data structures in depth? I feel like there are always 10 other technologies I need to know more urgently (eg, more bash, Linux, testing frameworks, deep learning, c++ libraries, linear algebra, common security mistakes/attacks, OpenGL, etc)
Given the bulk of the things you've listed here, which seem to serve very practical purposes, maybe never. I wouldn't call data structures a "technology" so much as I would label them as a theoretical underpinning to much of computer science. If your goal is to learn practical technologies (which is a good goal!) you don't really _need_ to learn data structures deeply -- they're just not a skill you need in day-to-da…
I mostly disagree. You won't need to implement them, but a working knowledge of the basics is the basis of any performance analysis and can make a huge difference in system performance in day to day programming. At some point all the small inefficiencies also add up.
I would go so far as to say that data structures and basic algorithms (e.g. Dijkstra) are more important to become a competent engineer than any of the practical tools he listed. It's like the difference between a mechanic and a mechanical engineer.
There is also a reason they are taught very early in a computer science degree.