Even on the mainland, vehicles and equipment are abandoned. At least in the US, if you drive through the countryside, every vehicle and truck that was ever used by someone is parked somewhere. If you go on a hike, and go through land that was once used for something, you'll find piles of old equipment, vehicles, materials, etc. It's not all that noticeable because there's usually much more land than the amount of stuff piling up. Even in my residential neighborhood, there's probably an inoperable car parked in a driveway every other block.

I don't think that things are always a quantum transition from "in use" to "abandoned," but a gradual decline. Stuff is just parked temporarily in case it's needed in the near future, or with the hope of selling it, and then gradually decays to the point of being inoperable. An abandoned car or truck won't just start. If a machine like a bobcat or bulldozer needs to be moved, it may require a running engine and hydraulics. Someone has to know how to get it going. Paying someone to haul it away may be expensive. If it's owned by a business, the ownership may gradually become unknown, especially in an informal economy.