Back in the 70's audiences had a different mindset and loved listening to double or even triple album concepts. I had tons of them (example George Harrison's "All Things Must Pass", Stevie Wonder's "Song In The Key Of Life").
I think it would have been a fabulous idea...showing a true artistic "Concept" album and given Queen more critical and commercial recognition and respect.
The contrasting names and artwork of the 2 albums...along with the extraordinary music on both...would have made them perfect as I have heard Brian call them "Twin Albums".
Queen's emergence as music pioneers and their main influential pieces that got widespread recognition were on both records (BoRhap, LOML, Seaside Rendezvous, 39, The Prophet's Song, You're My Best Friend, Death On Two Legs...Dedicated To, Somebody To Love, Tie Your Mother Down, The Millionaire Waltz, You Take My Breath Away, Teo Torriatte, etc. and so forth) so I think it may have proved an even better, more powerful artistic and commercial strategy, concept/work, perhaps appreciated and regarded even higher to release them as a double album.