>After you've been doing this for a few years you realize that code is code, whether it's running on a server, or in a browser, or on a desktop or mobile device. It's just code.

Except, it's not "just code". Front-end/back-end/ops, whatever, all have vastly different contexts. Hence the separate learning paths. You should know all three, but that doesn't mean you have to learn them at the same time or the same pace. You people are taking this chart way too literally.