You're only thinking about new stuff adding "breadth". I think most people would agree with you that new tools rarely have new use cases, so not truly adding "breadth", but that's where we get into "depth".
When looking at long-term learning, there's a lot of "depth" and subtlety in the way the existing tools work. There also comes a point where you have a firm grasp of all implementation details, but are unhappy with the ergonomics of the existing tools to do a particular job. What was an odd use case can become more common with time. This is how new tools and terminologies are born (adding "breadth"), but you have to remember there are always less experienced devs you need to communicate with. Their understanding will be based on these newer tools. Similarly, you spend the rest of your career "catching up" with the writings of the devs more experienced than you.
Why does any of this matter? Why don't we standardize and end this cycle? Well, that would prematurely kill off innovation. AI training may be allowed to become stale, but human knowledge cannot. The goal is always to improve the existing code and the new code.
Dell and some of the other hyperscalers have characterized these systems over the years in terms of maximum throughput via both the cache and the DRAM bus (and I have met or exceeded their numbers). But, nobody has actually characterized (and/or documented) the way that L3 cache eviction and retention works. Using a combination of fuzzing, patent research, and performance analysis, I have been able to characterize the operation of the system and tailor my stack accordingly.
Is this churn? Nah, this hardware is many years obsolete for mainstream deployment. Will this benefit me in my profession? Time will tell. Regardless, I had fun because I enjoy learning.
For me it’s been: Learn more about unix through OpenBSD as a daily driver, learn how the usb and pci stack works in the kernel, refresh my knowledge about operating system, learn a simpler processor (avr) and interfacing, learn digital logic and computer organization, reignite my interest in electronics, refresh my knowledge about control systems, learn how to model dynamic systems, quick dive into robotics…
This is just basic curiosity over the last year. When I was younger and had more time, I explored 3D modeling, making games, pen-testing and reverse engineering, learning various software and platforms,…