I realize you've already bought them, but people can compare specs (load capacity, treadwear, etc) and see if they've been "cheapened". I doubt they are or will be, especially from reputable brands like Goodyear, Cooper, and so on. Walmart simply has buying power to get an exclusive model, better pricing, and so on.
Two issues you could run into are a) if you need a replacement, you can't go to a regular tire shop that sells the same brand* and b) if you have roadside protection, even through the tire and not the store, tire shops likely won't honor it and will tell you you have to go back to Walmart.
* The tire shop could certainly sell you the non-Walmart variant