The reason it won't hold an automobile is that the real-world versions that the model is based on aren't *designed* to hold an automobile. An enclosed auto-hauling trailer is a very different thing.
These vicious machines are called "toy haulers", and they're intended to carry a couple of dirt bikes (motorcycles) or perhaps an all-terrain vehicle (little four-wheeled horrors whose only virtue is that, occasionally, they remove their foolish owners from this plane of existence).
The "furniture" provides a basic self-contained living space that allows the owners of said toys to drive out into remote areas (like the desert around here) and tear up the fragile ecosystem, while providing a place to sleep and keep the beer cold.
I recommend that the reasonably-armed figures in your photos engage and destroy the darned thing before it can be used as a base to to terrorize innocent wildlife.
Allen