Upgrade parts is a market, people think they are better with such parts even if they are bad drivers. It is their choice to buy even if it is their fault to smash the car to all kind of objects and then think aluminium parts will hold better.
Indeed the lack of warranty on high priced engines is absurd. I have seen a lot like loose crankpins, to fast broken or worn out conrods, splitted cilinders, loose piston-clip at the first start etc. and the warranty handeling is always different.