WWE was able to explode because they took guys that were established names across the country and brought them together under their great promotional skills and maximized their potential.
Now who these days can you say is a Hogan, Piper, Orndorff, JYD, Shultz, Volkoff, Ventura, Valentine, Tito that you could just plug right in with a Slaughter, Snuka, Muraco, Sheik in a promotion that already had a 20 year chokehold of the major Northeastern cities.
It just can't happen anymore.