For places in the US that use salt on the roads (upper Midwest / northeast), vehicles suffer from corrosion before drivetrain issues in my experience.

I would never buy a used car that has had lived through winters in places where roads are frequently salted.

I think they will, especially once the battery gets slightly larger and chemistry gets further refined. 1000 equivalent cycles times 300 miles of range per cycle is 300,000 miles. Takes about 20 years to get there, so for commuter vehicles, will almost certainly want to replace by then.