>>92835758Grimes was the kind of guy who hinged everything on his own hard work and academic success. The very fact that Homer could compete and succeed, without a fraction of the talent, pretty much broke him. Even though Homer got where he was because of Burns's complete lack of caring towards actual safety, Bart bought a shitty factory for barely anything, and Marge legitimately loved Homer.
Frank Grimes was the kind of guy who expected everything to favour the guy who works hard, which, while fair, is inaccurate. The Simpson family were opportunists - Homer even went for the Power Plant job just by showing up the first day. Bart took the opportunity to get the factory. Grimes could have easily done what they did in the same position, but he's unable to understand that luck and taking the opportunity have as much to with success as your intelligence.
Grimes was in the wrong, because he was unable to comprehend that a factor other than intelligence entered into life. It broke him, when pretty much every human being understands this.