In the end Walmart may stop selling guns but they have not yet where I live. Most retailers look at the profit per square foot when evaluating a line but the hassle factor of doing bussiness is greater with guns than many other items. You need a semi-intelegent person to handle the paper work properly for guns where you do not for socks and underware.
Sears quit the gun selling, Kmart gave up around here years ago and I suspect Walmart will do the same in the end. But we now have other big box stores to carry on. Dicks and Bass Pro sell guns and there are still several smaller gunshops that will sell and trade guns as well. Life goes on and the last new gun I bought was one of the new Remington autos. Most of my new gun purchases were made and sold 50 plus years ago.