What would cause engine bearings to fail on a well maintained G with about 150K miles?

I thought it might be the start and drive with minimal warm up time, but the debate rages all over the nets as to whether warm up time is actually required or not on a modern car. so I am not convinced. ideas?

 

Bearing failure could easily be caused by what you call minimal warm up especially if your car isn't garaged and sits out in the weather. All my cars are garaged and warm up depends on how long I have to wait for my wife by myself 3 to 4 minutes. And then I stay off the throttle for at least a mile until my oil gauge reads below 80 psi between shifts...Gary

 

Not changing your oil regularly or driving with low oil for extended periods of time could also cause the problem.

 

Which bearing failed? There are rod bearing and main bearings. If you had more than one bearing fail, it wasn't caused by wear but more likely a mechanical problem such as lack of lubrication due to bad oil pump, oil dilution, coolant in the oil, overheated oil, and so on.