Henry, asking you if an engine needs a rebuild is like asking a barber if you need a haircut.
I'm joking. A little bit.
Remember, the qualification: "unless you have some other reason to split the case;" and this is for 3.0 and 3.2 cases only, not the magnesium pretzels. E.g., low oil pressure, case leaks, internal noises, very high mileage, etc.
Re DIYers. As a reputable engine building shop, you have to consider the possibility of come-backs and factor that into your rebuilds and costs, or refuse jobs that are too risky for you. That's why you charge $30K+ for a rebuild (and I know you put the precision and care into it to earn that money). But a DIYer doesn't have to do that.
Re bearing shells: These are not wear items in the conventional sense, because the crank floats on a wedge of oil and does not touch or "wipe" the bearings in operation (unless you run low on oil or oil pressure). If they measure within specs, and don't have visible damage, then a DIYer should reuse them. They have already proved themselves in service. Much better to do that than get a new set of bearings that are out of spec to begin with!
We've gone around on this before, and you have avoided answering directly, so let me ask again: At what point do you think the bearings should be replaced? Any time the case is split, even with zero miles? 10Kmi? 50Kmi? 100Kmi? Based on what criteria?