Petrol prices

[normal rules]

The only reason average mileage per car has gone down is because ownership of cars per household has gone up. So a family that did 15000 miles per year in their one car ( pretty average ) now does 7500 in their two cars.

That is certainly a factor, Normal Rules.
Why do you think it is the only reason?

Does the changing pattern of work and commuting not play a part?

For the purpose of this discussion, the point is whether batteries would need to be replaced early.
If more vehicles do fewer miles per annum, then the batteries in those cars will last longer, will they not?

I’m no expert in ev battery tech Albie, but these new lithium batteries rely on charge, then use, then recharge. They need to be cycled I think the word is.
I’m unsure if a car that is sat around a lot would benefit from this. Ie if it is left to gather dust, does it’s ability to take and hold a charge diminish without proper use.
I used to own some rechargeable batteries a few years ago. Only charged them a few times, and after a few months I went back once to use them again and they would not take a charge at all. They were knackered. Different tech I suppose. But it makes you wonder. I’m sure someone on here may know different.

And yes, there is more to average miles than just car ownership. I think it’s a major factor though. I’ve seen some stats from 2014-2018 that’s shows a steady increase in ave car ownership per household in the uk in most regions.