The avarage bike around here retails for about $1500, so $15000 in a single swipe isn't bad. I have seen an entire bike rack being pulled out of the ground using a truck and winch, so yes it does happen.
Research has shown over and over again that penalty is seldom a factor in decision making, gain vs perceived risk of getting caught is, and stealing a single bike is still a felony.
You don't need a tow truck license to own a flat-bed, craigslist is full of them.