Times were pretty bad in America in '78-81 - hostages, malaise, high gas prices, high interest rates, inflation, 55 mph speed limits, etc. but got way better by the mid to late 1980's and things have been on a roll since. What was acceptable in 1980 for driveability is pretty far removed for 2018. 1986, less so.
I wouldn't want to drive a 14" tired, softly sprung, no swaybar'd, slow ratio steering, 3.8L V6 in 2018. Not with ALL of the traffic around me going 25-30 mph faster than it did when the car was built. Bolting on the best bits from the later cars can make an early car liveable a modern world. That is the only reason ALL of the earlier cars (except the very desirable ones, W31, Manuals, etc, of course) didn't go to the crusher.
If you couldn't easily bolt a better motor into a G-body, there wouldn't be a G-body forum and the early cars would be worth their weight in scrap.
"Nostalgia" can drive like @ss sometimes. Keeping a non rare, non important, non significant car 100% stock is masochism. People do it, but they are only hurting themselves.