The OP of this thread seems to suggest that failing the HSC is the be all and end all of your life, I pity any of you so foolish as to suggest this almost more than I pity those who failed to take the HSC seriously.
If we are to take failing as obtaining rank lower than 50.00, that effectively means that 50% of the state fail. With the HSC however, seeing as it is nearly impossible to actually fail and not be accredited with HSC (believe me tried), It is best to look at failing on a more personal level. High level students capable of marks >95 who achieve 80 have 'failed' more than a lower level student expected to score <60 but manges a 70.
Ultimately it's just about getting into the course you want to do and if you can do that you have suceeded, but lets be honest anyone who truly believes that they know what they want to do at this stage in their lives will be lying to themselves at 99.9% of the time. Few, if any of us have experienced enough of the options in life to understand what degree and potential career is of best fit to us.
The HSC is also not the only means of admission to a tertiary institution, my UAI was abysmal but i sat a general aptitude and intelligence test (STAT for those of you who are interested) and scored in the top .01% of the state, my marks far outshine every one I have compared to including the USYD pharmacy students who are required to take the test (almost all of whom have UAI's>90). Long story short, I got straight into uni.