Yes you are right about the additional 30 minutes however DC is in hands of WarnerBros and those guys are not comics savy they just care about profits simple way to compare is how many Movies, cartoons, games etc have Marvel and DC made to date.. clearly Marvel has the upper hand.. they could have made a Green Lantern movie, game, cartoon series or of Shazam but no..
In fact i am sure they must have used the same Doomsday type of the Justice League..