I think to use cars as an analogy for light ga aircraft is slightly flawed. A better analogy is houses, new ones are not necessarily better than older ones. Newer ones may have better ergonomics or insulation and be more efficient. Older ones might be built solid with materials or construction techniques that it would not be cost effective to use nowadays. Some people prefer newer, some prefer older. There will be designs that stand the test of time. Of the certified aircraft I have flown in my entire 160 hours my 2 favorites were built in 1958 and 1960.
The big thing is condition, like houses a 15 year old poorly maintained house can be far more tatty than one 80 years old.
In terms of tatty aircraft at schools. That is a difficult one. Appearance is important and does reflect the pride the owners take in their aircraft but training aircraft do work hard with inexperienced pilots. Tatty aircraft may suggest financial shortcuts but not necessarily. When I was training sometimes one aircraft may have been just back from a refurb and look really nice while another looked quite tatty as it was next in line. I knew they were all well maintained. The refurbed one looked much newer despite them both being about the same age. The old tatty one could easily be the nicer flyer.
If you are willing to pay a premium, I think perhaps you should consider trying to find a better condition aircraft rather than seeking out the newer air frames. But remember the owner is going to be a whole lot more upset if you damage that nice aircraft. If you are going to break the nose wheel off something may as well be an old 152, plenty more where that came from.
