Baby Jupiter's Huge Weight Gain

Is it because that when a sun first goes all sunshiney the new solar wind pushes all the unclaimed gas around it outward? So in our case the outer planets had a richer and and constantly-repleneshed source of gas in front of them to collect along their lazy slow orbits - like a snowball rolling down a mountain? And we were left with only enough collectable gas to fly a kite in?