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

But people already had this entire debate decades ago when disc brakes were first implemented. If you are racing or using a lot of braking power, discs are obviously better, they have better heat dissipation, they are quicker to repair and replace, more predictable for analog/dumb traction and stability control systems, and getting them rusty and dirty isn't a concern because you are racing and/or using the shit out of them. And most of the disadvantages became of little concern to consumers because when the consumer market moved towards automatic transmissions and smaller displacement engines people stopped engine braking constantly and were instead clearing their brakes off at literally every stop so dirty disc brakes stopped being a common concern. But the downsides still exist and is why disc brakes haven't taken over all applications.

Like yeah, drums have less heat capacity and worse cooling, but the entire point of regenerative braking is that you don't use them as much and so heat issues don't matter, only a small fraction of your braking force will use the physical brakes. 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.

>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.