I've had my Alamosa's since 2012, too. The sole lugs are worn pretty smooth, but not peeling anywhere. I've done about a dozen trips in the double digit miles apiece just in JTNP in those - plenty of boulder hopping, scrambling, general cross-country stuff. Several shorter little desert hikes, too. 200+ miles in the Sierras. 100+ more in Golden Trout Wilderness ( where the trails are a soft, dusty, pack train-ground "delight" ). Various other trips also pop in my mind as I think back - I'd say I have close to 600 miles on mine, not including wearing them in town on warm-up hikes, which is usually on an asphalt bike path.
I'm really surprised!
See a review of Keen shoes here:
http://www.trailjournals.com/sunshine2013cdt
At least two hikers who walked 6000 miles in various pairs of Keens - I guess if you stick with a brand that long it works for at least some people!
I will say I've noticed my husband's Keens are now starting to have the lugs separate a bit at the mid-sole "crease" so he's looking at a replacement pair soon. Then again, in addition to almost all of these hikes he also wears his to work regularly.
I'll be so annoyed if it turned out my pair is an anomaly, since this brand fits me so well.