The truth is that car engines almost never wear out. They suffer either a catastrophic cooling or lubrication event (low coolant, low oil, excessive oil drain intervals, sludge buildup, detonation) or they have a metallurgy/gasket failure from too many thermal cycles.
If inertial forces were the largest then the aftermarket forged rod and piston people would be out of business. Stock internals can run at red line forever but increase the horsepower of an engine and they eventually break. Why, because the power stroke force overwhelms the rods and pistons. The inertial forces haven't changed.
Here's a FEM analysis of bearing load as a function of crank angle? I'll dispute your claim of inertial loads being the biggest.