You seem to be hinting at an inverse relationship between looking fit and success in the water.
Without having any evidence to support my argument, I will venture to say that there is a weak direct releationship.
Swimming is much more technique-intensive than either cycling or running. Therefore you CAN be a hog and still motor in the water. Obviously at the fastest levels it becomes important to be void of fat, but carrying that extra weight around has many less adverse effects when you’re floating as opposed to when you’re fighting gravity while running or cycling.
Come to Masters swim in Colorado Springs if you want to see some fit swimmers. Wow.