I think that if you have a word with people who own Ford cars with their little '3-pot' engine you will find that they have exactly the same problem---is it in fact the same engine which has been done as a Citroen/Ford collaboration? I have heard (but cannot guarentee the truth in the statement) that part of the problem is that people have not been putting the correct oil into their engines.
In many ways, the older cars are far more "eco-friendly"in that you could repair a lot of the car, rather than throw the defective part away and replace it with a new (often expensive these days) part. Before I bought my current 'day-to-day' car (a 1.9t/d Skoda Fabia) we ran a Citroen Psarra diesel estate. Very comfortable car, economical and very roomy. BUT various ECU units were beginning to show their age, and although none impacted the safety of the car, the fact that the warning lights came on meant that it would have been a MOT "fail". When I ascertained the cost to replace the ECU units, they amounted to more than the value of the car, so a perfectly sound car got consigned to "the great scrap-yard in the sky" because 2 or 3 non-safety-related electronic units could not be economically replaced---progress?