If we're talking about at what point a motor would start to allow blow-by past the rings, and just basically be "worn out", Is it safe to assume that the difference we're looking at is the 180* motor goes 130k - 150k miles, while the 160* motor maybe showing the same wear by 100k. (???)

Most posters in this forum are asking about hobby type motors that are in weekend cars, and would take 50 years to see 100k mi. I doubt the wear issue is a factor in these discussions.

I run a 160 stat in my car because I've seen evidence at the strip that tells me it makes more power there than it does at 180. Also, with a 160 stat, if I get stuck in traffic (or idling through the staging lanes) on a hot day and my temp climbs, It takes a while to get to 200. If I start at 180 and get stuck in the same traffic, It's a much shorter window I have before its at 200.