I used to like shopping at Walmart and also used to buy their clothes. Lately, it seems as though the quality of their clothes is declining. I have had the same problem with some of the things I have bought from Walmart as well. I haven't bought anything recently though.
I started having the same problem so i just stopped buying shirts there cause they seem to get worse instead of better.
There are some really great clothes to be found at Walmart, but there are also some really crappy ones. Inspect the item before you buy it, then keep the receipt. Walmart's return policy on clothing is very lax. They'll take pretty much everything back within 90 days. If holes form, take it back! Exchange it if you want! By their own policy it shouldn't be breaking so soon.
I have never purchased clothing from Walmart. The clothes they have for sale at my local Walmart do not look like it will last very long and its very flimsy.