apart from christine my naughty van i stopped working on peoples car engines that were made after the mid 1990's because they all became a pain in the backside. i realised with working on christine modern cars have a shelf life like most things nowadays and are not really designed to repair easily, so off to the scrappy they go and buy another. it keeps the money going round....
The BMW diagnostics software for my 2000 2.8L beemer is readily available on the net so I do look after it myself, its got 24 valves and variable valve timing ex and inlet so a bit complex. Its at the limit of what I will look after but I thought I should “upskill” myself.
The achilles heel of older cars like this is the black boxes which are numerous and oem replacements ridiculously expensive, used ecu’s etc require complex re-programming to swap over VIN details, way beyond most people but bmw forums can help gifted amateurs to do it.
Even skilled bmw mechanics find it hard to look after older cars like mine, the oem diagnostic software was designed for windows XP and BMW are not about to update it, so the mechanics have to dig out an old laptop to do the full diagnostics, it gets expensive quickly if they start swapping out black boxes to find a fault, so as you say down the scrappie it goes, or it gets sold for bugger all to someone who can fix it.