There exist professional mechanics, and there exist oil-change technicians. The professional mechanic has literally hundreds of tools, of dozens of different types. The oil-change tech has maybe a dozen tools that he uses in an average week. The professional mechanic studies his craft and learns about suspension, brakes, engines, transmissions, electrical, fuel delivery, spark delivery, sensors, ecus, interior parts such as window motors, air conditioning, fuel pump replacement, diagnosis, etc. The oil-change tech can find the oil filter, screw it off, and screw on another one. Sometimes without even over-tightening it.

The "Wordpress Guru" is far more akin to the oil-change technician than to the professional mechanic. He likely does not understand HTTP, let alone TCP/IP, he might google CORS when he has a problem, likely copies code from Stack Overflow without understanding it, and has heard of Big O notation but has never had to apply it to his work. Honestly, I'm probably closer to that extreme than I would like to admit, but I do strive to understand ever line of code I'd be git-blamed for, and think that I understand two levels below the technologies that I do use on a day-to-day basis.