In order to even get close to PRIDE, Dream would need to sign some big names, champions, recognised fighters...and at this moment that is almost impossible. At it's pick, PRIDE was a big rival for the UFC. Dream will never reach that level.
The UFC is just too big, it has become just enormous.
It broke a lot of barriers, has taken MMA to other continents/countries and it will continue: Europe, Australia, Asia (Abu Dhabi)...and soon they will do it in South America (Brazil imo).
The key to becoming great is going global with MMA. And the UFC is slowly doing that.
Note: i loved PRIDE shows and i also think Dream shows are impecable and amazing