See, if you really think about it, it wasn't that Biggie was "lazy" or didn't have a work ethic. To finish a DOUBLE ALBUM while being in a car accident is still pretty amazing if you ask me. People saying Biggie was "lazy" dont realize, he too had to co-write Kim's album, WRITE ALL OF JUNIOR MAFIA'S DEBUT! Guest appearances, more concerts, recording his own album in late 96 etc. It's just that pac was constantly in the studio for him and no other projects.
Pac was writting for MC Hammer, working on a project with Chelle, heading the Gridlock'd soundtrack, etc.