Single post in ability to upgrade the daycare

No support. Yes you can get infinite adoptions in the main series games, but I think there's one problem you are missing. In the main series the daycare holds one egg for you (even if others would have been produced in the meantime) and you MUST ADOPT THEM ONE AT A TIME. In PFQ you can adopt them in multiples of 6 if you have enough adopts. Plus all of the above points