Want to make a Long Bet [1] on that? Years ago I would've never thought a private citizen would be delivering cargo to a space station with the goal of landing on Mars, but here we are. Reality can be unpredictable.
His unforeseeable future wouldn't be possible because no entity could do it with sufficient resources and will right now according to him.
Also , assuming we have the theoretical tech to sample a big set of cancer cells from a patient - collect a big list of all the unique characteristics, create a large collection of drug molecules targeted at all those characteristics with very very high specificity, and give them to a patient, won't this cure him in very high likelihood ?
Is a strange straw man to invoke about a future technology.
Teleportation is also a strange analogy to make for what is essentially our current cancer treatments plus miniaturization which has a fairly clear roadmap.
There are two reasons why cancer is so difficult to treat: (1) cancerous cells ARE your own cells that are behaving differently, so distinguishing cancerous cells from non-cancerous cells is very difficult. And (2) cancer cells are constantly evolving, so even when you do identify such unique features, the cancer mutates and changes this identifying feature. Decades of research has been devoted to identifying such "Achilles heels" of cancers that allow them to be uniquely and sustainably targeted by therapies and the number of successes can be counted on one hand. We already have technologies that allow you to identify unique features on cancer cells (e.g. monoclonal antibodies) and deliver chemotherapeutic drugs just to those cells (e.g. antibody-drug-conjugates) and they don't work too well.
Cancer is hard and nanomachine research is in its infancy. I can't predict the future, obviously, but I can guarantee you that people won't be using nanomachines to treat cancer for the forseeable several decades, if ever.