That's a shame, I have a feeling it is probably harder to move charcoal powered products where I am (Connecticut) in the winter, and for some reason, Walmart seems to moves items to clearance based on how long it takes to sell a UPC. Warmer regions probably don't have the same sale droughts on outdoor items (grills, weed whackers, etc), so it's probably a lot less likely to be a clearance item there.
The crazy thing is, I will put money on them restocking these grills around April-May in the Northeast, right back at $288. Makes more sense to let them take up room on a shelf than to let them go for 50%+ discounts. But, their loss is our gain I suppose.