Coal miners are cheap, easy to replace and have little negotiation power. Devs are expensive, harder to replace and have some leverage. Coal miners can take a pick or an axe with them when they leave. Devs can take away with them valuable operational knowledge with them that can bring to a competitor. Not comparable.

Plus, look at the job market. Every single tech company out there has been laying off devs in the last 3 years. If maximising productivity above expenses was so valuable, every tech company out there would be hiring like crazy because senior devs are cheap as chips nowadays. But they aren't, devs might be cheap but money itself isn't right now so they are prioritising lower expenses over increased productivity. Because that makes shareholders happy. And that's what every company aims for.

Maximising productivity is only an absolute goal in the minds of devs not in the minds of executives.