I expect that Keith will be gone soon. He will be revolving doored to some non-executive directorship in some large company.
But I don't think this will solve the problems of the Labour party. Keith may have been a stuffed shirt with as much charisma and political vision as a breezeblock, but the problems fundamentally aren't so much personal as ideological. The Labour party has been trying to emulate Blairism at a time when that 1990s style of technocratic politics makes absolutely no sense. Corbyn tried to change the direction of the party to be more relevant, but we all know how that worked out. So it could well be that the Labour party just dies and is replaced by Greens or something else.