That's a great question, and one that city planners and public works departments think about a lot. From my experience, modern metal urban trash bins are surprisingly resilient, but their resistance really depends on the specific materials and construction.
The most common types you see are made from galvanized steel or aluminum. Galvanized steel bins are the workhorses – the zinc coating provides excellent rust resistance, and the steel itself is very strong. They can handle a lot of accidental bumps from service vehicles or shopping carts. You might get a small dent, but it's rare for a quality bin to be catastrophically crushed. Aluminum bins are lighter and naturally rust-proof, but they are generally softer and more prone to denting from sharp impacts compared to steel.
The real design focus is on defeating daily abuse, not just dents. The powder-coat or epoxy finishes are crucial. A good coating prevents scratches from exposing bare metal, which would lead to rust. The best bins also have reinforced corners, heavy-gauge material at the base, and seamless, rounded designs that help deflect force rather than creating a flat surface for a direct hit.
So, are they indestructible? No. A determined hit with a heavy object can definitely leave a mark. However, for normal urban wear and tear – weather, litter, casual bumps – a well-made metal bin is incredibly durable. The key is proper installation (anchored down) and reasonable maintenance. You'll see them last for a decade or more in most city settings, which is a testament to their built-in resistance.