Since STS has been working hard to REMOVE stats from vanity items, there's no chance this will ever happen. And if it did, then all you'd see is everyone who can afford it walking around with the "best" pet just for the stat boost. The point of a vanity is purely for looks, so it's working exactly as should be expected. Think of it this way: it saves you all that plat you would have otherwise spent because you just had to get the stat boost.