Mine runs great other than the use of oil. For me it comes down to why keep driving till it fails when I can do it now and have it working like new as long as im alive.
My rig has 285,000 on it - all my miles except the first 20,000. I replaced the head gasket at 220,000 but only because I was blowing huge amounts of white smoke and had Toyota red all over the bottom of plug number 6. It was pretty obvious the gasket was gone and pulling the head confirmed it. Doing predictive maintenance should be done when you know neglecting it will absolutely result in problems. This isn't true with head gaskets. Many of our rigs will never need a head gasket replacement until the engine needs a rebuild. Why incur that cost when it isn't absolutely needed. In my mind doing a head gasket replacement when the previous gasket isn't blown is like saying "eventually the transmission will wear out" and replacing it as a preventitive measure. Unless you have imperical evidence that the transmission will definitely wear out at a certain usage point (like 300,000 miles), why would you do it?
I've written about this before, but I believe what degrades the head gasket is heat cycling of the engine, not the total miles driven. Every time you heat up the engine from ambient, wear takes place. Once the engine is at operating temp, stuff is pretty stable. If you have a 60 mile daily commute, you may get 400k out of your head gasket. If you have a 3 mile commute, the gasket may fail at 120k. If the truck had a cold start counter gauge on the dash, I think the data would be very interesting, but since all we have is an odometer, the confusing data leads to may different opinions.