People are more apt to buy into an 'unlimited' plan. Road trips would cost extra (because you're gaining unlimited full-multi-day access to a vehicle), maybe something like $30/day + gas.
That's part of my point, though, that what the number is (or at least its order of magnitude), actually does matter.
For something like a per-person charge, if that number is high enough, for large enough families, people are going to start looking at whether they could be saving by using the per-vehicle pricing of buying versus renting. I'm also saying that this number must be high enough to be attractive for the car company.
> maybe not 100% electric, but maybe 100 mpg with electric assist.
I'd say that's misguided, then, because fuel cost alone is too low a fraction of total operating cost.
> Road trips would cost extra
So like today's cellphone "unlimited" data? In that case, sure, an actually-limited subscription plan would easily be attractive to a car company, since they could write in any limits they want and change them any time, as well as vary the pricing at any time.
How many consumers would opt for that instead of outright buying is another matter.
Still, $200 seems far-fetched in light of the average American 1200 miles monthly. At under $.17/mi (not counting deadheading), that might not even cover depreciation/capital cost.