I think it will happen eventually, where wi-fi will be included in the resort fees. Before that though, I wouldn't be surprised if an ISP gets an exclusive wi-fi contract for its' subscribers. Comcast is already testing free wi-fi in Jersey, at many NJ transit stations. Supposedly at the test sites, you just log into a specific website with your Comcast name/password and you're on. If the test goes well, Comcast is hoping to add free wi-fi across the country at various locations.
I could see Verizon, AT&T, Comcast etc ... battling over the exclusivity rights to free wi-fi at WDW.