KSL isn't about to be sold off any soon because it is a case of local domination of a market by one station through all forms of media, like WTMJ-TV-AM-WLWK-FM and The Journal-Sentinel dominate Milwaukee media. KSL Radio is the most listened to station in town, and the TV station has been the news bearer for years, and because Bonneville was so forward thinking, they also dominate over craigslist and the newspapers in the market when it comes to classified ads via their website. There's no way Bonneville sells off their crown jewel without at the very least, a contract with iron-clad directives like Pat Robertson did when he sold off the Family Channel.
There's other factors, like a heavy slate of local programming pertaining to LDS and local issues that isn't duplicated on the other stations. The only reason CBS moved to KUTV in the first place was NBC had to sell it off so CBS could make the channel switch with NBC in Miami for the better and more dependable Channel 4 tower and so NBC could get WCAU in Philadephia because CBS was stuck with KYW in the Westinghouse deal. They probably wanted to stick with KSL (and still do on the radio side), but all those factors forced the switch in 1995 in the first place. NBC wouldn't have went with KSL if they didn't know there was going to be heavy local control that they could usually wiggle out with when it came to other station groups. Since until the late 90's SLC was all-VHF, going with a UHF allocation like what eventually became KUCW in their market would've been seen as an insult. There was no way KSL wasn't going to get NBC.
NBC won't ever go to KJZZ. KJZZ is just as entangled in Mormon ownership (Larry Miller's estate) and they shoved out UPN, as was mentioned below, and quickly ran as fast as they could when MyNetworkTV turned out to be terrible, moving it to midnight until their affiliation agreement ran out. And KMYU is based all the way in St. George in the south part of the state; it's carried in SD as a KUTV subchannel in the Salt Lake City metro. Nobody wants to be stuck on SD these days (plus Sinclair doesn't usually take NBC affiliations in the first place), and as a subchannel, forget it.