Labor costs are low. In inflation-adjusted dollars, today's CM makes a few dollars/hour less than they did in the 1970s and 1980s. Meanwhile, don't get me started on what has happened to Median Household Income in the last decade, especially in the private sector. Those of you who don't remember the days when private sector jobs paid better than government jobs don't know what you are missing.
As
@Jeffxz mentions, Universal has to operate in the same business environment, and they don't have WDW's advantages of 25,000 cheap acres, a "local government" that's in their back pocket, and a steady stream of over $2B in annual revenue from 27,000 grossly overpriced hotel rooms.
WDW's problem is summed up by the $425M New Fantasyland vs. the $265M Hogsmead.
WDW has become a bloated bureaucracy, incapable of operating efficiently.
Rather than correct their institutional problems, their "fix" is to delay investments, cut quality, and raise prices.