The problem with that logic is that I have heard of NO t-belts breaking on a 3.2 or 3.5 even with 150k miles on them. I have, however known of MANY water pumps and tensioners failing by that time. These are the original OEMs, not replacements. So, you should be replacing the water pump and tensioner as maintenance and using the same belt.

Precisely. It's a new item amongst old items. The harmony will never be the same. That said, unless you replace everything, leave well enough alone. You're just asking for trouble.
That just makes NO sense at all. Dont do any preventative maintenance, just wait till something breaks then replace the vehicle?