Early air cooled leafs aren't doing anyone any favors when talking about battery aging.

I think the numbers of those early leafs (a lot were sold), their horribly degraded batteries, and their consequently low sales price make the numbers appear a bit more dire for resale EVs as a whole than they are in reality (breakdown loss of resale value by model and other EVs are doing much better). However, I think it is also true that EV resale values are lower than they perhaps should be due to used battery fears.

OTOH Leaf is a proof that old batteries can be replaced and upgrade an old car.

Original Leafs were sold with a 24kWh capacity. Current ones have 48kWh for the same price, and 64kWh replacement batteries are available. So you can go from half of the crappiest range to 3× more range than when the car was brand new.

Old batteries with reduced capacity don't even have to be thrown out. There are projects that reuse old Leaf batteries for grid energy storage (any capacity is useful when they're sitting on the ground).

I'm betting that the current-gen mainstream cars will benefit similarly, especially that production volume is orders of magnitude higher now (lots of brands share the same platform and battery modules).