Towing capacities aren't realistic, completely unachievable

My issue is with the truck manufacturers advertised towing capacity. That number is completely unattainable based on cargo weights being so low. Use the 21,000 lb number for example. The cargo weight is 3200 pounds. There are NO trailers that weigh anywhere near 21000 pounds that wouldn't overload the cargo cap, so you'd never be able to tow what the manufacturer boasts, the manufacturers are misleading consumers big time. Just annoying.