These items were released nearly a year ago - in case you had not noticed, Walmart and Target no longer have them in their planograms. I don't think that TRU does either - the AT-TE simply sold through and was very popular (not to mention $50 less than the Falcon).
The Falcon sold through in most areas as well, but can be found on clearance in some areas still. However, TRU still has shelf space for it at full price.
That's why you don't see AT-TE's at retail anymore. It's actually really simple.