FWIW, I had two aunts who I am pretty sure had electric WHs that lasted
at least 34 years. One from each side of the family and about 2000 miles
apart-- my mother's sister in law in west Texas and my dad's sister in
upstate NY. Both were finally replaced. I think the one in Tx did have a
catastrophic failure (major leak), but as I recall the tank of the one
in NY was actually still ok, but a pipe going to the heater leaked, and
it broke off at the WH and could not be removed, at least easily, so
they just replaced the whole thing. Larry