Burnett's recent scorecard hasn't been very pretty. The Contender was dropped by NBC after one season, as was Martha Stewart's Apprentice. The original Apprentice is still alive and kicking, but ratings have been way down so far. Even Survivor has taken a hit; it's still a top-10 show, but it used to be much higher in the ratings. Plus, its host has indicated a desire to leave the show after his contract expires. The only other network reality shows that come to mind that even register as blips on the radar are The Amazing Race and (arguably) Big Brother, neither of which is a Mark Burnett production.
ABC Wants 13-Episode The Conners Season 2; Cast in Negotiations