I hear your pain but theory seems a bit far fetched. There are no balancers in your engine. You have SOHC V6, balance shafts are only somewhat needed on 4 cyl engines. Even then you can just take the off fairly safely.
Actually I'm not quite sure what you have had replaced unless we are talking about automatic belt tensioner. Which doesn't have to be but good idea to replace when replacing timing belt.

Did anyone actually took engine apart to look at bottom end? Without inspecting the bearings death sentence to engine is a bit premature.

Sounds to me that dealership just trying to get you to go away.