As I said before, for the marketing departments a few knots on the competition makes a difference. They want you to achieve the cruise speeds and fuel consumption figures in the glossy brochures.
The data prove that at a mixture of around 50F ROP you're giving the engine the hardest thrashing you can give it. Many engines tolerate the abuse. Some don't. If you're interested in maximising the longevity of an engine, it's better to sacrifice some fuel efficiency by going further ROP, or better still to sacrifice a few knots in return for greater efficiency by running LOP.
The reason aircraft manufactures and engine manufacturers and maintainers don't really care is because everyone knows what causes any and all engine problems: Pilots.