I suppose they could, but it's not very likely. There's no doubt that if they return, there would be new ones avaiable. I would prefer another method of making Poke Balls myself, but I'm not sure if others would like the idea XD I figure tossing this suggestion out in this thread is better then cluttering up the D/P forum further with an idea that doesn't need a room of it's own.
Instead of only making one Poke Ball a day with apricorns, perhaps we could collect materials and give them to a 'smith' of sorts - in return he would make you a special ball for a price. Whether giving him the materials once would unlock the ball permanently for purchase or having to find materials (Which, like the shoal salt and shells in R/S/E, would respawn daily) each time I can't decide. I would prefer the former, since it isn't like the smith would simply give you those Poke Balls 'on the house'. Depending on their function, the price would vary between that of the standard balls.