This is exactly right. It's all very well saying you should run an older XYorZ but when any kind of minor repair at a garage, or even routine items like suspension bushes runs well into three figures it makes much less sense to buy cheaper older cars.
For a lot of people a £500 bill (easily achieved these days) will quickly become £6-700 by the time the credit card company has had its due.
And as Omegas (as we are an Omega site, some people might still have one
) aged, I suspect it was relatively high garage bills for relatively simple work that made them depreciate hard, and in turn made even minor service type work uneconomical in the minds of some - those who argue its not worth spending £800 to sort out the worn out front suspension on a car worth £500...
If you have to rely on garages for virtually everything, old cars don't really work unless you are buying them for their long MOT, then rinse, repeat...