The advantage of going to a good school is the students, not the teachers. Not only is the mindset better, but they can support you if you do badly. The main advantage of going to a good school than a worse one is that you don't have to completely GUN the external exam to do well; others in your cohort will "pull you up".
For example, if destinyliang didn't go to baulko, he actually wouldn't have state ranked eco. Not to take anything away from him, but because of the fact that the guy who came first had an external/internal of 99, destiny's internal mark was dragged up higher than what it would have been had he gone to a lower ranking school, where he would have likely been ranked 1st and had the same external/internal. If this had happened, he wouldn't have state ranked, because his external was two marks lower than his external, and wasn't high enough for a state rank. State ranking with different external/internal marks is uncommon, and will only occur at schools which have more than one person who can state rank.
In other words;
the ADVANTAGE of going to a good school and being ranked average is that you don't have to carry yourself, you can rely on others to help bring up your internal assessment marks
the ADVANTAGE of going to a not-as-good school and being ranked high is that you determine your own atar. In this sense, it may actually be EASIER to state rank at a lower school since it's actually easier to be first. However, this of course doesn't mean it's any easier to get the required marks to state rank.