Ferguson's legacy is decaying right in front of his very eyes and turning to dust.
His legacy is a big part of the cause.
He didn't fight the owners, he embraced them.
He didn't build a sustainable structure within the club, he made himself the king of his own fiefdom.
He didn't leave a hungry, young squad with room to grow and develop.
He left a squad of aging players on huge contracts because he sacrificed the future of the club to the alter of his last couple of titles.
He didn't leave a style of play because he never really had one in the first place - he was always happy to leave the tactical details to his assistants.
That assessment is obviously harsh - I mean clearly the man had unprecedented success and enabled the club to develop from a big club to an absolute behemoth.
But what he left in terms of structure, playing staff and footballing culture for his successors was toxic. Compare and contrast to Mainz and Dortmund pre and post-Klopp.