While NBC began looking for a replacement host soon after, it took some time for Season 8 to come together and then NBC held the show until midseason on the schedule.
Secondly, The Celebrity Apprentice had way too long of a gap between seasons.
Season 7 kicked off in January of 2015, so it was two years between Season 7 and Season 8.
That’s a gap that Sherlock might be able to get away with, but not all shows can.