Is the MLB era of big boys over?

Is the era of MLB have big players over? Many known players like Bartolo Colón, Pablo Sanvdoval or Prince Fielder, it seems like now there aren't as many big boys as there used to be playing in the MLB, this could be down to more advancement of over all fitness and training in the sport at earlier levels but it seems like the "big boy" type is starting to die out.