When the Vivo barefoot came out (the one with the removable liner that I think had the sub-name "ultra pure") had a specification of 4oz each (1/2 pound a pair) and cost in the ballpark of $80 (so yeah, really expensive).
What I always wondered was how good were they on the trail?
I've hiked short distances in the $20 shoes listed above when water crossings were within almost back to back, but they were impractical as the sole just wasn't thick enough to protect your feet from sharp rocks and poky sticks.