So a patch went up today for Super Mario Maker which had the following notes:
•“Create a course” scene: a small element was added.
•Condition(s) for increasing the amount of useable parts (in the level editor) were added.
•Various changes meant to improve the gameplay experience.
That second one is the interesting one. Having had some time with the game, I can see that what it really means is that the major complaint about SMM is now gone.
About 15 minutes into editing my level, "day two" items got delivered. About 15 minutes, "day three" got delivered. It seems that Nintendo actually listened and fixed a huge complaint. So bravo to them!
Edit: For clarification, it seems it might be based on how many blocks you place in the Create mode. There's no official word on this right now, so it's all speculation and testing, but spamming a load of garbage blocks into the editor is working for people here.
So if you want everything quickly, just fill up levels with utter garbage.