I like analogizing between multicellular organisms and nation-states, in that both are complex systems built upon the coordination of many individual systems (cells/people). In the case of cancer, what we have is essentially rebellion, a failure of control: individual cells decide to stop cooperating and instead begin competing with the body that houses them. So I agree with you... rebellion is always a threat to any system of control.
Unlike actual rebellion, though, there's no way the cancer can "win" in the sense of taking over control of the body. If only cancer could realize the futility of its crusade...
This is of course ridiculously ambitious compared to the current state of the art, but I think it's a reasonable start to countering the claim that a general cure for cancer is impossible in principle.
That said, I don't want to say that cancer is fundamentally beyond us. I think cheap sequencing and emerging highly targeted DNA editing systems, along with better understanding of the immune response to cancer, will get us most of the way there in a practical sense.
What you suggest is more or less what I mention; you could, say, try to add back some genetic machinery for the cancer cells to recognize that they're defective, and then they kill themselves. Or help the higher level repair mechanism (the immune system) target cancer cells.
To my understanding, trying to fix anything at the level between whole cell and DNA mutation is much harder.
It's like arguing that entropy always increases and therefore fighting disease is fundamentally hopeless, or requires non-logical approaches. Yes, of course "ill health" can't be cured in general, but we can drive disease rates ever lower.
Sure, but no one disputes this. Silicon valley investing in cancer research does not imply anyone takes such a silly position.
any person's cancer is millions/billions of semi-independent, extremely complicated, poorly understood state machines, with a variety of mutations, constantly interacting and evolving against any treatments applied and immune reactions.
imho, cancer is a fundamental disease/property of multicellular life, and trivial reductionist perspectives completely out of touch.