They used to have the game after the superbowl of course...but most people forget about football as soon as the superbowl is over. So they moved it, in attempt to make the game less ‘forgot about’. I don’t know if its worked - but I see why they did it. And frankly, even with the game after the superbowl, a lot of top tier players chose not to attend.
I think the Pro-Bowl needs to go away, it is the least viable of the all-star games.