I work with M/MUMPS on a daily basis. It's no surprise that it is a primitive language, as it was developed in 1966 to run on PDP-7 computers, less powerful than a raspberry pi. But M is still very relevant today because it is the power behind many (most?) of the electronic medical health record (EHR) systems in the world: Epic, Meditech, VistA (from the VA), Allscripts (more here: https://en.wikipedia.org/wiki/MUMPS#Current_users_of_MUMPS_a...). Note that it is also extensively used in the banking industry. I have heard it said that at least 50% of people have their money run through a Mumps financial system during electronic fund transfers. Mumps is very fast and very stable, IMHO because of it's lack of bells and whistles. GT.M's version of Mumps is serious about it's moto of "Rock Solid. Lightning fast". (https://www.osehra.org/content/fis-gtm).

The most important part about any computing system/language is the resulting application. Yes, it is nicer for programmers when they have advanced language features. But ultimately, the test of how "good" a language is should really be about how useful it is, and how widely it is used.

The wheel is very old technology and yet still very important.