My wife is thrifty too, at least on the big stuff. I'm definitely in your wife's camp on driving the wheels off a car you've already got versus buying a new one, even if it's more efficient to operate.
In our case, we needed a car anyway so it made sense to go EV and we went with the smallest one that would do the job. Having owned an EV for a few months now, I will never buy another ICE car but we will keep the old ICE minivan for long trips and large hauling chores. By the time it dies and needs to be replaced, I figure there'll be plenty of EVs that have the range, charging speed, and capacity to do what the van does.
My current plan is to buy a smallish IC vehicle, drive it until it dies as I usually do, then buy an EV. I can't justify the cost of an EV at their current prices though I'd definitely like one. The value for money simply isn't there for my use-case.