B.I.G. and Pac couldn't stop the shiny suit era, they couldn't stop the South's takeover, they wouldn't be able to stop Kanye's takeover. They wouldn't be able to stop the societal changes that led to change in hip hop. Also, Jay-Z is arguably hip hop's greatest businessman, he has extreme industry push and connects, he's a label head, he's the greatest PR'd rapper ever. If Pac were alive I don't think he'd be bigger than Hov right now. I think Pac would have moved on to activism and acting.
If B.I.G. and Pac were alive they would have cosigned Drake...just like Hov has, just like Nas has, just like Bun B has, just like Ghostface Killah and Raekwon have, just like DJ Premier has, just like Jay Electronica has, just like Kanye has, just like Prodigy has, just like LL Cool J has, just like AZ has, just like Slum Village has, just like Little Brother has, just like Fat Joe has, just like Andre 3000 has get the fukk outta here.