I'll take the airline experience of today over that of the 1970's-1990's.
Food: Yes, the presentation was nice in those glory days, but hygiene and quality was not necessarily as good as it is today. I like the fact that the chemicals and sprays that were used to preserve the food, to keep it looking good and give it "flavour", are not used anymore.
Seats: I remember flying around the world with Delta's RTW airfare at $5,000- $6,200 in the 90's. It allowed me to use DL, SQ and the old Swiss Air. Well, what I got back then in First was a seat that was uncomfortable and offered the pitch of a domestic F class today. No lie flat, no suites and not even a cradle type option. Electric controls? Not very effective. IFE? It was a little TV that came out of the armrest. Any one remember those horrible little cassette tapes of movies that they would hand out?
And as has been pointed out, the smoking was awful. I would come off the flight smelling like an ash tray.
IROPS: Think it's bad now? It was positively awful way back then. The data management systems were terrible.
It wasn't the airlines that were so good back then, but the flying demographic. Flying was still relatively expensive up until the 1980's. It acted to keep alot of people out of the airports and off the planes. And if anyone has noticed, there were far fewer morbidly obese slobs and folks with their bogus disabilities making a nuisance of themselves.
One good thing today is that if someone is physically impaired, he/she can still travel. In the good old days there was little or no assistance given to people with real disabilities. Today, someone with a physical impairment is usually treated with some respect and given the appropriate assistance.