I've owned my 1.3 (replaced pierburg now) for 11 years, dad had it since 1989 before that. I still use it as a daily (in fact i also have a new VW so every other day) and i still prefer it to the new car. Though both are different sorts of drives so hard to make a direct comparison. Did break down the other month, replaced ignition system and all fine now (so far!) A 10 year old car needs things doing to it as well, so its no different to a 25 year old car that also needs things doing. If you dont want to ever do anything, buy a new car every three years, and thats still no guarantee!
Granted mine isnt a GTI, but it is still 25 years old, 175k on original engine, and still great fun to drive!