Some of it was because of stricter gun laws and regulations. You use to find ammo and guns at every little mom/pop store but most quit cause of what it cost and the time they had to put out for keeping the license and paperwork up. I remember as a kid going to the small mom/pop store around me and buying 22 shells for 1 cent a round and you didnt have to buy a full box go in with a nickle and walk out with 5 rounds didnt matter how young or old you was.I reckon Wal-Mart is only reacting to what they have to deal with. Just like selling reloading supplies in Riverton, WY is ok - keeping guns out front at Admiral and Memorial in Tulsa might be riskier.
I remember Kmart, TG&Y, Otasco, Skagg-Albertson's, JC Penney, Sears, Montgomery Ward all carrying firearms and ammo at their stores.
I wonder what's changed?