I just see consciousness as another ability like sight. Sight is dependent on our eyes and brains. Consciousness relies on the brain.
How come some people are colour blind? Because their eyes or the way the brain interprets what the eyes sees isn't quite working properly. Surely, some of what our particular brains do or don't do well is genetic. Talents tend to run in families often- eg. music, maths, sporting abilities. As do vulnerabilities to mental illnesses it seems. Any illnesses in fact.
On top of that- what you've experienced to date. Say your parents were magically transported to a different country, a different culture and religion and they were either made massively rich or, massively poor before you were born. Wouldn't all those things affect who you are now? Say either the very best or very worst things in your life hadn't happened- wouldn't that affect who you are?
I don't think your brain created who you are randomly. I think it is simply an organ that has a certain amount of genetic potential. Then, it gets nurtured or abused as we grow. It simply observes what's going on around it. Learns to interact with its environment and creates an idea of self as a result.
As to why we are even aware. Who knows? Maybe it was just an evolutionary hike up the ladder. Like an opposing thumb. Why wouldn't it give an animal an advantage over animals to be self aware? It means they can get better at exploiting everything else consciously!