Would they have given him a 6 year contract if that were the case?Quite simply he's being used as a buffer manager. A stabiliser until a better manager comes around.
I guess my thought is that anyone after Fergie was going to look shit with this team, so get someone in who can be steady if unspectacular then move him on when he unsurprisingly doesn't meet the clubs standards of winning things. After which the memory of Fergie has faded somewhat and you bring in your big manager who can only seem a success after what has preceded with Moyes.
Just some thoughts I had when Moyes was announced really.