I think a programmer is someone who writes programs, regardless of the quality of the code. Substitute spreadsheets for typing if you think its more appropriate. Not everyone with domain expertise knows how to use a spreadsheet, and not everyone who uses spreadsheets uses them as well as someone that, for example, writes software for a living (and not all of the latter use it as well as someone who only uses spreadsheets!) But good luck finding someone who's only job is getting hired to code up a spreadsheet. The vast majority of uses are to allow someone with just enough skill to create something that performs a job function in an automated way, which in turn makes another job that much easier. Once upon a time, it would have been a persons job to perform the calculations and updates that a spreadsheet makes trivial.

It would be foolish to think that the same will never happen to the vast majority of our jobs.

I see that it could be true for many desktop and mobile phone applications but who should develop the operating systems, embedded applications and backends? It is a full time job just to learn all the programming languages, libraries, frameworks, standards, protocols and other related things.

Well, the "programmers" in operating system and embedded domains are usually electrical engineers who learned how to write code, just enough to apply their domain knowledge. A programmer in the usual sense, that is someone graduated from pure software school, will have a hard time competing with those people.