Why aren't there good results from fat injections in the lower eyelids? (photos)

I've seen a ton of examples of filling the upper eyelids or tear troughs (upper cheeks), but never seen a filling of hollows above the orbital rim after lower blepharoplasty. I definitely see such results in old publications when solid (pearl/dermis) fat grafts were used - in these photos the pretarsal part of eyelid became less prominent after grafting, but what prevents from achieving this with liquid fat? Is it fat migrating from this area or something else? Can somebody fix this?