For reasons I won’t go into, I just installed another water heater. This one, nominally a GE that’s made by Rheem, has a perfectly aligned anode rod access port. This view shows the insulation filling the port, after removing the plastic cap:
A bit of excavation reveals the top of the rod:
And the 1-1/16 six-point socket fits exactly through the port and mates perfectly with the rod:
Unlike the never-sufficiently-to-be-damned Whirlpool, no metalwork is required.
Oh, and they have a very nice drain valve at the bottom, with wide opening that shouldn’t clog with the slightest trace of sediment:
Overall, it looks like a definite win.