I don't pay $100 for runners, but that is right around the average price for them. Got my last pair on zappos. Free next day shipping and free returns.
Never gotten blisters in any footwear other than dress shoes (knock on wood), but have had hot feet in boots and longed for trail runners after a long dry day on the trail. I usually don't take my shoes off until camp regardless the footwear. Carrying camp shoes is sometimes a PITA, but I do that when wearing trail runners too...or go barefoot.
My wife (ultra-marathon runner) is quick to blister and found that socks are a more important factor than the shoe.
But you do get my point about longevity, right? I've got a super heavy pair of Montrail ATs that are going on 16 years old. Probably well over 3000k miles of Alaskan/Canadian bush and mountains on them. Soles are pretty worn, but they are comfortable as heck. Will I wear them mid summer on the LT? No, but then again I don't wear trail runners on a mid winter snowshoe over-nighter.
Boots and trail runners are different species with different strengths and weaknesses. Knowing what they are and using each at the correct times will make hiking much more enjoyable.