Sure, that's because a bike doesn't promote emotional attachment, unlike a car. A cyclist enjoys biking, but he generally doesn't attribute that enjoyment to his bike -- he would just as happily swap for another, just as I'd throw out my old running shoes and buy a new pair.

Cars, however, promote more emotional bonding. I think because the car moves under its own power it feels more like it's alive. I press the accelerator, the car does what I tell it, and we form a bond just as a rider forms a bond with his horse. On a pushbike you're always keenly aware that it's you who is doing all the work, and the bike is just a tool.