It's because the historical perspective in this article is really lacking, despite that being the premise of the article.

Not only does the author seem to believe that C was the first popular high-level language, but the claim that hardware provided stack based CALL and RETURN instructions was not universally true. Many systems had no call/return stack, or supported only a single level of subroutine calls (essentially useless for a high level language but maybe useful for some hand written machine code).

FORTRAN compilers often worked by dedicating certain statically allocated RAM locations near a function's machine code for the arguments, return value, and return address for that function. So a function call involved writing to those locations and then performing a branch instruction (not a CALL). This worked absolutely fine if you didn't need recursion. The real benefit of a stack is to support recursion.