It really depends on the Walmart. Walmart (like any store) caters to the locals. If the local population supports the fabric section, it stays, if not, it goes. My local Walmart has one. Anyways, buying ripstop nylon is a real hit and miss. Sometimes they have it, mostly they don't. I have been fortunate to find it a couple times. I bought all they had when I found it.
I've taken a vow of poverty. To annoy me, send money.