IF you ran all your subs off just the right channel do you think all of the bass track on the source recording will be reproduced?
Below 80 Hz, yes. The recording studio examples you are talking about is different. Drums, bass, etc have lots of output above 80Hz. This higher frequency output is what determines stereo L and R and gives us imaging. Below 80Hz simply does not do that. It is not a question of how it was recorded. That doesn’t even enter into it. Because the waves are so long, when playing back it no longer matters.
The proof of that is while you can hear a difference in the recording studio you cannot with just the subs at home. I have run them every which way just to prove this to myself. Also a lot of subs that have L and R channel inputs, if you look at the circuit diagram they are summed inside. L and R are there for convience.
Can’t say as I blame them. If the cost is an extra irrelevant RCA connector vs answering this same question a hundred times a day till the heat death of the universe I would throw in the RCA too.
Thus, clearly, the device above is useless, unnecessary, superfluous, and ill-advised.