You answered your own question...when you reach the tournament and can look your players in the eye and say "we've been here before" or "we've played teams tougher than our semi-state/state opponent in OCTOBER (no coach would actually say this out loud, lol) it is a huge advantage...and with the recent tournament results at the 6A level, its nearly impossible to argue that these are true statements.
Combine that with the commitment to the sport being more serious in central Indiana in terms of pay, teaching schedule, facilities, etc...and the enrollment advantages in most cases, which can not be ignored.