I remember my pilot training in the 70's. Round slide wheel and nautical mile ruler with compass. Everything, including fuel consumption, true air speed, density altitude, course correction, etc.... had to be done by hand while flying the plane(with no auto pilot)under instruments. You had to dial in VOR's and NDB's to discover your position while being tested. Cockpit management was a busy task. Then came the first computer in 1978 called the "Navtronic". It was a handheld thing which was lousy. If you used it on a test you would fail. It wasn't accurate enough.
I remember flying a Baron 58 and if it wasn't for the corner of my eye I would never have seen the needle deflection and would have blown right thru my fix. It happens real fast at 200mph. Throw in bad weather and lot's of radio activity in busy airspace and flying a twin was a dicey thing to do without a copilot, or at least savvy helper.
Today it's easy breezy. That is until something takes out GPS. I even got spoiled on Loran C. Without it there were times I would have had no idea where I was.