Right, but let's be clear about our terminology here. Automation in mechanical/manufacturing isn't being done by CS grads with skills in RoR employed as software developers. It's being done by MechEng graduates armed with FORTRAN compilers who write a lot of code but don't consider themselves to be developers at all.
How different is a MechEng writing FORTRAN for mechanical engineering from a MechEng writing RoR for trendy widget bean button SV startup?
I'd argue they're both programming, which is sufficient to reap some of the benefits of automation. Software engineering can be described as applying engineering to programming. Any company that benefits from programming would also benefit from the increases in efficiency, reliability, performance, etc. software engineering would bring to programming.
Because in scenario A the main skill being applied is mechanical engineering and in scenario B the main skill being applied is RoR.
If everyone who ever writes a line of code is a "software developer" would you include an Excel VBA 10-liner writer? Probably not, and nor would that person include themselves, they're an accountant (or whatever).
I think of work like FFTW and the Tensor Algebra COmpiler (TACO) as software engineering.
Mechanical engineering didn't have its Lisp. We do.
The steam engine was more of a productivity multiplier than Lisp could ever dream of.
Tool A should modify itself to become Tool B. And Tool B should modify itself to become Tool C and so on...
A mechanical engineer designing a new manufacturing technique or robot is most certainly using their field to automate their field. Most of computing exists because electronic engineers used their field to automate their field. Software is not unique in this respect.