SoC is how all maintainable software is built. A function for A, a class for B, DDD-spec'd modules and features, databases on separate machines, API definitions, queuing systems, event systems, load balancing, web servers.
You don't even need to think of the web to see how content and presentation are different. Try editing a text file with hard line breaks in and you'll quickly understand how presentation and content are orthogonal.
Please don’t be so condescending. We all know what separation of concerns is.
The comment said “web development”, and it’s inarguably that in the history of web development there have been at least a couple of major misapplications of separation of concerns, which have had practically everlasting negative consequences.
Read what you’re replying to before you reply to it.
You don't even need to think of the web to see how content and presentation are different. Try editing a text file with hard line breaks in and you'll quickly understand how presentation and content are orthogonal.