30 years ago fuel injection was a lot different than it is today. The computers were primitive, and there were plenty of points of failure in the air box wiper contacts, multi-relays with 15+ pins, primitive temperature sensors, a separate set of ignition points to fire injectors(remember the old 1975+ VW beetles?), etc. Factor into that no malfunction light to flash you a code, and the troubleshooting could get pretty hairy. What you are saying is like comparing apples and oranges as far as a modern FI system is concerned.
As far as the OP is concerned...ask yourself what is more likely to go
100,000 miles without a failure..a traditional gearbox, be it a transmission or a transaxle, or this new DSG stuff that I've heard nothing but bad things about.IMHO there are far fewer points of failure in a traditional gearbox. As soon as you add hydraulics, two clutches(!), that expensive special fluid those DSG boxes take(!!), and the mechatronic unit, with failures that seem to be a big issue with the VW version of these things, it might give you pause about buying one.
Best...
Chris