To everything there is a season. As it happens this is not the time for a Labour government. No matter who had led Labour into the last election the mood of the country was such that they would have not done much better that Ed Milliband.
In the meantime there is a job to be done to put the country back on a sound economic footing, reorganise the welfare system and tax dodgers, and tackle extremism. This is what the present government is committed to doing. If they succeed they may well be re-elected for a third term.
Meanwhile Labour has a breathing space to examine itself. All this self examination in full public is not altogether damaging. At least the party is not sinking into oblivion as is the LibDens. Whosoever is elected this time round is very unlikely to be electable, to become PM, this was recognised by far stronger candidates which is why they didn't throw their hats into the ring.
There are those waiting in the wings who will step forward, probably after Labour loses the next election, and these are the ones who will have the capacity to lead Labour into government, by which the Tories will have make themselves unpopular and be searching for their new leader.
As I said, to everything there is a season.