Aaaand well shit, that’s my problem, isn’t it?
Because of the nature of S1, there was the built in restriction of the mundane world. All of the rivalry and angst had to play out without the crutch of unrestricted magic. The little bits here and there were odd and creepy anomalies instead of the fall-back answer to everything.
S2 kind of brought that in as well, but it starts to go off the rails pretty quickly – Rumple and Regina are magic users, Emma’s away for a bit anyway, but her freely using magic is 2 seasons away at this point. So things kind of start to go a bit screwy, but then once you bring in Greg and Tamara, and before the Storybrookians realise that G&T know what the fuck is up, there’s the whole idea of keeping shit schtum as to not arouse outside suspicion. Like even Regina and Rumple are invested in that to some extent.
Neverland works-ish, because even though they’re in a world with magic, Emma’s still learning, Rumple fucks off, Regina is being vetoed on magic use by the heroes – but the magical MacGuffins start in earnest around this point and they never really stop coming.
By S4, there’s no reason to curtail the use of magic except for the on-again-off-again issue of it always having a price, or it being out of control. And when there are no restrictions, logic flies out the window.
Magical items and spells are conveniently available whenever needed, and conveniently unavailable for the same reason and I really feel like the flippancy towards the world building really kicks up at this point (ALSO BECAUSE FROZEN JESUS CHRIST) and you start to get A&E’s palpable resentment towards fans who were asking for the modicum of world-building consistency that the earlier seasons showed?
There needed to be a restrictive element to the magic in the show in order to keep it within that mythical “S1 feel” and that was the only thing they were unwilling to go back to.