Some really good points on the ultra-fast depreciation of SE tech skills. A relative of mine is a mechanical engineer, well past retirement age and still going strong in his 2-man consulting shop because that's what he loves doing. He works with precision manufacturers, automotive suppliers,... all very cutting-edge stuff, helping them develop new product lines, manufacturing processes,... He says the core skills that he's using are still those that he learnt in university several decades ago.

I was actually surprised because I heard so much about crazy new materials like carbon fibers, graphene, technologies like 3D-printing,... but apparently what makes a machine break are still the same things: mechanical stress, heat dissipation, friction,... new materials and processes might change the coefficients, but not the (mostly Newtonian) physics (my interpretation btw, not his words).

One could say the same thing about software engineering - true fundamental advances in algorithms and data structures are sufficiently rare that it wouldn't be a nuisance to keep up with them. But the %-age of how important those basics are relative to the extremely fast-changing landscape of tools and frameworks is much smaller (plus, one could argue that even the fundamentals see a lot of shifting ground in CS, with neural architectures, differentiable programming, not to mention quantum computing).