I've heard that every brand/company pays certain amount to be displayed on whatever store shelf they decide or can afford...i guess this is not the exception - i wonder if this cheap looking knock off paid an specific amount to be craftily placed next to Playmobil or if TRU put those sets there randomly...
The term is called "slotting." And you're right, many (but not all) big-box retailers charge slotting fees for shelf placement. Different retailers approach this differently; some want a set cash amount per item, others determine the cost based on the number of stores the product is going into, or by linear inches of space that will be allocated.
Companies can pay these fees directly or other times by shipping free product. There is a fair amount of negotiation that goes into this, and shelf placement could certainly be discussed. It can get expensive, but isn't illegal, and retailers are usually quite up front with their requirements.
That said, I'm not in the toy industry, and don't know how TRU handles slotting (if they do at all).