The overwhelming majority of increase in recent years has been due to the cost of labor. As recently as 2018 WDW cast member minimum wage was $10 per hour. By 2026 it will be $20 per hour.
DVC has often asserted that 75% of a resort's operating budget goes toward wages and benefits for employees.
I don't want to turn this into a political discussion but the two are undeniably linked. Arguing that Disney should have done more to control annual dues increases is basically arguing that "the people who make the magic" shouldn't be earning more than $12 or $15 per hour. And given that they're drawing from the same labor pool as competitors like Universal, and workers are backed by a union representing 45k+ at Disney alone, such low wages were unrealistic.