Also I wanted a series, could have been a 1 or 2 season arch and then Netflix or whoever could flail off into other characters and deeper cannon and non-cannon lore, and I would have had my fill and moved on.
Wicked was published in 1995. Making this movie might have made sense up to 2009, but now? It's a sentimental cash-grab. Same reason they're making Gladiator 2.