To each their own. Ever read a copy of The Double Gun Journal. It may somewhat explain the mystery that perplexes you.
The double guns I own:
sxs 12 ga Ithaca cicra 1912-1914 right when they bought out Lefever 30" F/F
sxs 16 ga Spainish made imported through Kassnar arms circa 1970's
sxs 20 ga Spainish made
sxs 28 ga Spainish made only stamped with Eibar and has really funky engraving

Turkey and Waterfowl:
12 ga 870 with a synthetic stock


As you see I do not own an O/U so I am not qualified to really judge your passion for them. I have been caught with a O/U 410 Fausti in the training field due to Kennel Rules. It does handle nicely. But I prefer the sxs's.