I was thinking of it as all encompassing but strategy really is 95% of this game.
No, challenges are a mucher bigger part of it. In most seasons, that's what gets your team the majority at the merge and determines who controls the endgame. And the majority of winners have needed late challenge wins to succeed, especialy in the F2 era..

Vee F4 IC, Brian last 3 ICs, Jenna lasr 2 ICs, Romber last two ICs, Chris last 2 ICs, Tom last 3 ICs, Danni final IC, Aras F4 IC. Oher winners needed Kelly or Dreamz or Amanda to win challenges and eliminate people they couldn't beat.