The problem is entirely due to the labor and compensation for mechanics. The Mechanics get a shit proposition. If you are smart, you do not do it. Exhibit A, mechanics are paid a fraction of revenue but are 100% responsible for warranty. Imagine if you shipped a bug, you are told to work without pay to fix it. That is what a mechanic does.
It’s even worse than that: someone else shipped the bug and you have to work without pay to fix it.