>They last as long as the expected tank life these days.

Kinda seems like a self-fulfilling prophecy or one could even say planned obsolescence.

It does. Unfortunately, homeowners have no interest in paying for premium units or investing in maintenance. So manufacturing precision goes into exceeding the 8-10 year warranty and little more. My hope is that the current and upcoming electric and natural gas pricing increases will lead to more awareness of heat pump water heaters, which last quite a bit longer.

Or an accurate estimate???

I don't really get how you can extract a conspiracy out of something lasting as long as the manufacturer expected it to last.

Many manufacturers design things to wear out or break earlier than they would with minor changes to the design.

It is an accurate estimate, done to increase sales.