Grades don't necessarily measure the level of intelligence of a student, therefore attaining a raw score of 40 is not exclusively for those "super super smart people" and by no means is it an elusive goal. Provided that you consistently put in the effort and maintain a positive outlook on your studies then anything is achievable.
However to varying degrees I think that hard work, luck and natural ability all come into play as well. For instance, I have friend who is an amazing writer, she works hard and I'd even argue has (to an extent) has natural ability to write eloquently with no apparent effort. She usually maintains high scoring grades in English however, for our language analysis SAC at the beginning of semester one, she received a grade which was quite low in comparison to her usual mark (it was still a decent mark though). Despite being a hard-worker and having a natural aptitude for writing, she made some minor mistakes and unfortunately she was just unlucky.
The fickleness of VCE means that anything can happen. It's really hard to determine the difficulty of attaining a raw score of 40. Although grades are not exclusively a matter of effort, I think that one thing is certain that through dedication and determination reaching a particular score is never made impossible.