Performance being pretty high on even a basic Tesla doesn't help things either. The insurance market in the UK is very expensive anyway and any excuse to wind up premiums they'll gladly use.
I have had my side mirrors and windshield repairs covered.
Yes of course, it's part of the actuarial calculation. As cars age they become more expensive to repair and eventually will cross a boundary where the insurer will write them off on any type of accident, rather than trying to repair. This naturally increases the base insurance price.
OEMs in the EU are only required to produce spare parts for 10 years after a model is withdrawn, which is a strong indicator of when write-off becomes the primary option.