Nice find on that Miyata!
Actually, it doesn't amaze me what others may pass on. Rarely do I have the time to target an estate or garage sale and its usually just a spur of the moment thing. Doesn't matter what caliber or brand, but bikes without air in the tires, cobwebs, garage dust stuck on oily, greasy bottom brackets and drivetrain are a lost cause in the eyes of most. The majority call them just an uncomfortable old 10 speed.
As usual, junk to most but treasures to me
I've found items for a few bucks or piled for the dumpster that turned out to be worth $$$$$. Small, odd pieces and parts for rare old machinery that nobody would recognize. A fave was an old jumpsuit some thought was mechanics overalls but turned out to be a rare vintage auto racers suit. Scrounging further and found a leather helmet from the same era. I like finding oddity and rare car parts that make no sense to most. Usually these are items I like to keep or use and something I couldn't or would go out of my way to buy.