Sad...but IMO, MOST businesses if pushed would cave-in: Doesn't take much to make the weak-willed (and probably closet anti-gun anyway) owners/CEOs to fold.
I hope Kroger doesn't cave, as I often shop @ King Soopers (Kroger-owned) here in The Great State of Colorado. Should Kroger fold, likely King Soopers would, too. Will then have to "retire" my Kroger Discount card (brought from TX where they HAVE Kroger supermarkets, and useable in King Soopers here). Even Smiths in NM probably would go GFZ, too, as they also are owned by Kroger (along with Albertsons, I go to Smiths when I am in Rio Rancho & ABQ -- and use my Kroger card @ Smiths).
So Kroger folding would make large ripples in the pond...
As per IMO then, if MAD keeps pushing, eventually MOST businesses will fold and become GFZs. At that point, we OC & CC people will have hardly anyplace to go, whether it be grocery shopping, general merchandise, services -- or whatever.
Yet just possibly, as some restaurants have done recently, maybe NEW businesses will see the anti-gun-posting/GFZ trend as an opportunity, and clearly cater TO "gun people," so maybe there is an evolution of sorts taking place presently.
But who knows...