@ALB,
It's not that "some" builders don't want to do it-- it's 99% of engine builders who don't want to do it.
The reasoning goes: nobody is going to drive their car 100,000 mi, so why do something with a chance of ruining a $1200 case when it won't make any difference until 15 year from now.
I found a machinist who agrees with the idea. He's in an extreme minority.