My experience has been that people who are good at the bottom layers of the stack are good with the top layers of the stack, too. And if they're unfamiliar, they can ramp very up quickly.
My comment addresses the perception that "OMG programmers today know nothing; this is what a Real Man looks like". Someone learning web development has spent a lot of brain-space on learning a level of in-depth knowledge that also looks magical to someone who hadn't.
As it happens, I too think that the things you learn lower down the stack tend to make you a better engineer, whereas what you learn higher up the stack is too often an unedifying schlep. High-level systems spend a lot of complexity solving problems created by the layer underneath. (This goes 10x for web frameworks.) Low-level systems are more tightly constrained by the boundaries of the possible, so they spend their complexity on more fundamental problems. The same amount of time and intelligence spent learning the ins and outs of Angular yields less transferable skills than learning how compilers work. But if you need to build a web startup, compiler expertise on its own won't help you.
It's like learning physics vs biology. Sure, physics is more fundamental, and a physicist learning biology usually has an easier time than the other way round. But a research biologist has also spent their time acquiring an immense amount of expertise, and fundamentally we need medical advances more directly than we need confirmation of the Higgs boson.