This might sound harsher than intended, but given how the performance of a speaker is driven by the interaction of the enclosure with the driver parameters its kind of like saying a saxophone is just an enclosure for a reed. Or a car engine carburetor is just an enclosure for the air that connects to an engine. The acoustics of the enclosure dominate the performance of the overall speaker, especially at the low end freqs.

There is a big difference between just making a box, making a box that looks nice, and making a box that cooperates with the specs of the driver to make a good speaker.

You might be surprised how awful the specs are for a bare driver hanging by its wires in the air without an enclosure. It is very much like the analogy of a musical instrument reed.