> latter case if the person who added another database/programming language/web toolkit/etc managed to achieve something with in in a short period of time.

This one bothers me. It's brought up all the time. And I completely agree that adding a new tool or feature adds risk and technical debt. But if there's no other way to do it... I work in a corporate VBA shop. 90 percent of our work in the last year was in VBA. But next year is looking like python, R and JS. How? Requirements changed. We got handed some projects in machine learning and we delivered, crudely but still. While in the technical sense we 'could' have coded it all in VBA it's not practical in the slightest to do so.