Ford could have been such a great villain... and Bill knew it.
It's no secret that Stanford Pines' fatal flaw is pride. He couldn't bear to destroy his work - even to make certain Bill couldn't get to earth - and he was paranoid about Fiddleford stealing his grand unified theory of weirdness. And when you have pride like that, it's not hard to step into entitlement.
Ford deserves happiness, doesn't he, and the world has been cruel to him. He's worked himself to the bone all his life, he was violently teased for his fingers, his own brother betrayed him, he was forced to attend Backupsmore of all places, but he STILL managed to reach for the stars, he was STILL worthy of a muse's divine attention.
The world never did anything for him. What does he owe it? Why not just... let it all burn?
That was Bill's own logic, after all. It's logic that easily excuses atrocities if you have the pride for it. So why wouldn't Ford jump at the chance to welcome Bill into the physical world with open arms? Why wouldn't he accept the power to bring the people that teased him to their knees? Why wouldn't he stand by Bill's side, become one of his demonic fold?
Because Ford is a better person than Bill. And Bill didn't count on that.













