THIS JUST IN:

TV based, mostly topless industry favors people who look impressive the moment you see them, more at 11!

It's not just Vince dude. Big guys get pushed in wrestling for the same exact reason, it just communicates a story and idea to you immediately. Big and or muscles equals power. When you see a tall guy standing there with less definition than the 5'2" dude standing next to him, it communicates that poorly even to people who have watched Cain fight.

It would do him zero harm to specifically target his pecs and and shoulders between now and the Brock match since the fight is fake, and it would make him seem more intimidating and the pre-match visuals would be more exciting.

Like even people who were already in great TV-shape usually do something different when they come back from a big injury because it trips the "oh shit!" switch in your brain.