>Rusted rarely exercised drum brakes are already known to be far more reliable than rusted rarely exercised disc brakes, that is why many vehicles still or had until recently kept drum brakes in the rear where they get far less usage and get 1/10th the attention as front brakes.

My ass. They might be "trouble free" in that you don't notice them not doing anything whereas a well rusted rotor will be very clearly cranky and/or felt in the brake pedal or steering wheel and perhaps the driver will elect to take it to the shop.

>Or in trailers brakes that are utilized far less often.

And which have a pretty strong reputation for always being in some degraded state or otherwise not working to full capacity.

>Ideally in an EV your physical brakes are 100% a safety item, not a common usage item, and so reliability should be the top concern

In which case a disk is far more likely to work, if poorly and loudly whereas a drum is much more likely to be completely out to lunch for some huge fraction of the cylinder's travel from a long ago seized adjuster or whatever.

Yeah, drum brakes "can" be made to work. I bet wagon style friction brakes "can" be made to work. But discs are just soooo much easier. Throw an 80s style stainless slider arrangement on it so pins aren't a concern and pony up for a galvanized or stainless rotor and it becomes a basically a "good for the life of the car" item if you don't go through the pads.