Why would that last be a good idea? You're throwing away a good business with 70% gross margins - for what? Okay, to concentrate on something that might be a go

Why would that last be a good idea? You're throwing away a good business with 70% gross margins - for what? Okay, to concentrate on something that might be a good business with 99% gross margins, but is the difference between 70% and 99% all that important compared to other factors, like the difference between is and might be? Not a rhetorical question; maybe there is some logic to it that I'm missing.