Walmart would be an absolutely terrible vendor.
Shisha brands seem to thrive on finding their own niche, selling to that crowd, and if they fail to please that niche they fail. Walmart would find the cheapest shisha to appease 50-60% of the people, mass produce that product, and do their best to undercut prices to put other niche shishas out of business. If you didn't like their product once all the other brands were gone then too bad. Thats just for tobacco, and you know its true.
I hate to think what kind of cheap cast, poorly welded hookah with a horrible draw and a common chamber heart they would mass produce and sell to undercut traditional, well designed and carefully hand assembled hookahs.
And forget about walmart being a vendor who will ship you replacement parts free(hookah-shisha.com), talk to you on a forum(mahir, john, gabe, etc.), send you replacement product when you show that their product has a defect(gabe of exotica), and generally give a damn about your smoking satisfaction.(i know i didn't mention a lot of excellent vendors here, but these were the ones that came right to mind)
In other words, No Thankyou.