And in many cases that led to an instant drop in productivity. Those old green-screen systems were not pretty but they were quite efficient to use.
Having worked on the system myself, they were right (this was as a noobie to both systems).
There is something to be said for a small, tight system.
This because the doctors insisted on using a DOS based patient journal, as they could operate it completely by keyboard while maintaining a conversation with the patient.
I speculate that one reason for this is that DOS allowed each program to have full keyboard access, while Windows and other GUI has to reserve certain keys for managing the UI (switching between windows etc).
Thus what was earlier a series of single key presses now involves holding down a modifier for the duration. And that is if the developer even remembered to put in a hotkey for said action.
It's just that software makers don't do it; most everyone thinks everyone loves to do things with mouse et al.
When Windows was developed, we had enough CPU power to do the basic tasks people wanted done with a computer at a reasonable speed - the idea was that spare capacity was being traded for user friendliness.
For some applications, even today, when maximum efficiency is necessary, purpose built machines ('soldering together the flip-flops that make up your logic and memory') are still used - it's just that it's often an ASIC that is fabricated.