I understand your point, but I hate waste. If there is a way to make wheels last much longer, I do it. On my road bike at 7,000 miles a year, it was 3 year life due to fatigue cracks at the spoke holes. After 2 sets, I switched to double socketed rims, and that has never happened again.

I never wore out the sidewalls on my road bike rims, but I rode it in fairly flat land. Now, I ride in a place with quite steep hills, frequent and long braking, and it wears the (406) rim sidewalls quite a bit, significant concavity on the rims after 9 years, even with frequent pad and rim cleaning, and not riding in the rain. Yes, that's a good long time, but a new set of wheels is not cheap; Why should I replace if I can avoid? I think the only reason the rims have not worn thru yet is because they are cheap single wall OEM Dahon rims, so the sidewalls are probably as thick as the center section. But I know they are not long for this world.