I've never heard of a vehicle other than a lemon or known bad design* have mechanical failures if the severe service schedules are followed.
I agree, entirely.
I'd add that a good number of current engines have coking, sludge, soot, oil dilution or oil temperature problems. Those engines do far better on quality synthetic oils, changed frequently. Example: The small oil drain holes on Corolla pistons tend to clog on non synthetic oils, leading to early oil consumption. A problem that is 100% avoidable with proper service.
Back on topic: Lower viscosity fluids are being used to improve the efficiency, as a result, lubrication performance has been decreased in roller and needle bearings. This is not conjecture, it is a fact that is going on industry wide in everything from electric motors to diesel engines. Needle bearings are failing more often now that lower viscosity lubricants are common.
We tend to concentrate on cylinder/ring wear, and to a lesser extent, rod bearing wear. But we often ignore the fact that engines are complex devices, with various components having differing lubricant needs.
