I agree that our problems run deeper than Allardyce, but he is making it manifestly worse, and sucking the lifeblood out of us like a tick (which is a fair analogy for what he is).
Firing him is no panacea, agreed. Walsh must go, and it should be a soup-to-nuts makeover in the organization. Everyone involved needs, at minimum, to make a harsh self-evaluation as to their part in how we got here.
And it will be a long, hard road back. We need someone that we, and more importantly the squad, can believe in again.