Let's compare engine life from pre 1995 to now. How long did you really expect your engine to last past 100k miles then? And how many miles do you expect engines to last past 100k now?
So yeah, older technology with an older blend of fuels worked fine. Just not as well and not as long as they do with today's technology and today's fuels.
1-1991 Golf GTI 367k original motor.
2-1972 SuperBeetle Unknown miles was in family for 20 years no rebuilds.
3-1991 VW Rabbit convertible 176k no rebuilds.
4-1995 4Runner 210k no Rebuilds.
5- 1985 Toyota Supra 187k no Rebuilds
6- 1969 Chevy stepside 200k+ no rebuild
7- 1981 Mazda RX-7 150k 1 rebuild
8- 1985 RX7 gslse first fuel injected rotary 200k+ stayed in family till mid 1990's
9- 1969 VW beetle motor finally died after 30 years of use
10- 1988 RX7 turbo rebuild before 100k
11- Multiple Nissan/datsun Z cars from 1972-1980 all over 100k no rebuilds 1980 280zx was totaled with over 200k several Z cars had over 200k
12- 1988 toyota celica 287k
13- 1985 4runner 150k
14- My first car 1977 toyota celica GT hatchback 187k totaled in a stupid fender bender...Miss this one alot..
Ive owned alot of high mile pre 1995 junk i had expectations of lasting over 100k cause most were purchased with 100k or more already. I would actually trust some of the older cars vs so called modern ones. All of this newer stuff i trust less and part with before 100k due to all the Gizmos and fancy safety crap that will fail and cost big $. Plus you have to have a laptop and dealer type software to work on most of this modern stuff. I do think modern engines are built well im just set in my ways and have trust issues lol..also mileage on alot of those cars were guessing on my part at best based on time owned cause most speedometers only went to 99999...
Edit: to stay on topic all were run on 87 octane except the 1988 turbo Rx7 i couldnt afford that fancy gas back then!