Tesla’s Elon Musk is raising an important question about job titles

Some of the job titles for professors are: tenured professor, full professor, endowed professor, assistant professor, associate professor, adjust professor, teaching professor, and professor emeritus.

Going back to the essay, job titles also help prevent people from being punished for not doing things they don't want to do which are outside their job title domain - at least in places with decent worker protections.

Suppose someone hires me as a senior DBA, then three months later moves me over to iPhone app development, where I have no experience. I do poor work, so the employer decides to cut my pay.

FWIW, there are job titles which are not so limited, like "Fellow" at some companies. So I think it's a mistake to say that job titles only mean Taylorism-style factory jobs.