Yeah it's really interesting, i can see in the not too distant future companies starting to make pattern body panels and glass for Teslas now they're becoming more mainstream but with the rest of the car like batteries and motors it'll be interesting.
I don't really see people making pattern batteries as each manufacture is so different currently, Tesla with their small round cells vs the rest with pouches of different sizes and styles.
But in the grand scheme of things replacing a battery pack might be the equivalent of replacing an ICE cars engine and gearbox, how often does that really need to happen?
Yes exactly its what hes failing to take into account, demand
Low volume ICE cars (and until Tesla M3 they were all low volume) dont have a multitude of pattern parts either.
The reality is they will function exactly like ICE cars once they are mainstream, enough sold to make pattern parts financially viable those parts will appear
Its a hard comparison but the Ev motor is more like the ICE gearbox and the EV battery more lik ethe ICE engine in complexity and cost
So where you would get a say 3-6 year old ICE that has the engine damaged either written off or an engine swap you would get the same for battery damage with the EV, and where the EV damages a motor again its almost certain you will get either a swap in of a part used one, or a rebuild like an ICE car.
Tesla like every car manufacturer wants their own bits used, and with young or rare vehicles they almost always will be. Once Tesla M3s get older then thats the point where a more significant pattern and refurbish process can start.
I think its Nissan who already offer remanufactured cells, Japan only I think, but its the sort of thing that will spring up, if there is demand
Going back to the insurance angle, I have some insight as I used to do projects at one of the UKs largest, with ICE vehicles they know a lot, history of teh manufacturer etc. When new they have this available to be able to fairly accurately predict the vehicle, new and rare cars will be loaded since they don't have nor will they use pattern parts. Its why imports are often grouped higher for similar cars, part availability will be lower wich increases claim costs as they often result in longer repair times = longer higher car and more expensive parts.
I am sure right now the ins cos are loading BEVs a bit cautiously until they start to get some true claims costs experience
https://cleantechnica.com/2018/05/15/nissan-begins-offering-remanufactured-batteries-for-leaf/