I think there are many who are 'aware' of cancer, but the cure is not that simple, and anyone proposing a single 'cure' is misleading the public.
There are over 200 different types of cancer, and they all behave slightly differently.
We are getting closer to curing some cancers, but it will take a while before we have real solutions for all of them.
That said, there is a lot available IN NATURE that fights cancer, and many of my hubs are about this. Toxic treatments are not the solution for a lot of cancers. Although they are curative for some, the side effects and increased risk for other cancers and disease as a result make it a difficult choice, even when it is offered as the best option. I wrote a hub about chemotherapy, which may help answer some of this question (at least the part about why someone would choose chemotherapy - I did not).
Understanding Chemotherapy: Choosing Your Weapons Against Cancer
To your question about why pharmaceutical companies don't invest in research, they invest in research for drugs they can patent and profit from. There are others out there doing research on natural cures, these are just not as well publicized, and while there are many nutrients that exist in the world that fight cancer from many angles, there is nothing that sweeps through and completely eliminates it.
Just as there are a combination of causes for the mutations that become cancer, fighting cancer naturally requires a combination of attacks from a variety of sources.