Artificial scarcity has been very profitable for Nintendo, and don't think Disney, who loves money as much, if not more, isn't paying attention. Teary-eyed kids at there being no Olafs does not register positive on their cross-benefit analysis, but Sabine, an obscure character only fanboys know about, now they may have something there, despite what J.V. has been saying about them filling the shelves, and making every character available.
I don't think they are causing short supply by choice. Stores only have limited shelf space and they don't want to over-order. So they are playing it self. None of the figures are sold out online, so you can easily get them for shipping, unlike said Amiibos.