I totally agree they're not coming out of this smelling of roses. I think it's a bit of both, they want as much money as possible but at the same time probably aren't against the notion that sold out signs increase demand, just as it did with the Wii. When Mario probably sells 20x more than Marth does, why focus on restocking Marth when you can restock Mario.
Would people be as chuffed with their Rosalina or Villager amiibos if they knew they could find them in plentiful stock everywhere? I don't think I would be, I like the fact that I managed to find a rare one. Increases the value for me (I mean personally, not resale wise). I'm not excusing the supply problems, I think they're ridiculous but I'm not quite as outraged as a lot of other people are.