A coupla things...
Except for some highly specialized single purpose shotguns like SBTs, our scatterguns are incredibly versatile. Even friend PJR's O/U with 30" barrels would do for HD in his trained and skilled hands. It also wouldn't be much longer than the 42" arbitrary max length for a "Serious" shotgun.
Like a friend of Pop's said ca 1960 while admiring my "New" 870, "A man with a good shotgun don't ever have to go hungry, and less reason than most to ever be skeered". Said friend took a Garand for a walk from Normandy Beach to Berlin in the 29th Division, and I regard his as an informed opinion.
With ONE 870 here, assuming a few choke tubes and 3" chamber, I can take any legal game in the state from rails to turkey and geese, use slugs on all three species of deer, obliterate pests like Nutes and ferals, play all the shotgun games and protect my family.
With TWO 870s, I can set one up for the defensive end and slug hunting, and the other for wingshooting and fun. Naturally, overlap is not only inevitable but a bonus.
Some of us have lots of shotguns,from Kreighoffs to H&R singles.Any collection or battery without a good pump is not as deep, IMO, as it could be.