[oneplane]

It hasn't gone down, it has expanded and as a result diluted the general base of knowledge. At the same time, that isn't as much of a problem as you'd think as most 'SWE' isn't really that, isn't more of a cookie cutter basic CRUD/Feed/CMS setting where real in-depth knowledge isn't required to make a product work 'good enough' and keep a job.

There are still plenty of people that actually do know the theory and actually do work on low-level stuff, but at the same time the reality is that the olden days of engineering aren't coming back; they are what is currently often referred to as the '10x engineer' type of work. It doesn't scale, it doesn't work well with others and it doesn't return on investment all that well.

Unless you need someone who works on hardware, kernels, compilers, runtimes or severely constrained constructions (query planners, memory managers, transaction engines etc.) it really doesn't matter as much as it used to.