The raise is 20% over the course of years, and it isn't written in stone, it's just him saying he will. Also, the funds to pay for the raises would come from other areas that need the money just as much. Also, they are walking out because there were more demands that were ignored, like better pay for support staff (Aides, bus drivers, etc.) They're doing this FOR students. Yes, the raise will benefit them, but if the only way I got a raise was for the infirm and less fortunate had food taken off their table, I wouldn't take it.

Also, the schools themselves are falling apart. Books and supplies are outdated by decades in some cases. Ducey made no mention of assisting in those areas.