Doctors aren't gods. They're limited to what they know. Long ago, they thought something couldn't be cured, but we have vaccines for that now. With the advancement of technology comes a greater area for potential for new breakthroughs. Not all of them will be life-changing, such as performing remote surgery on bananas, but you never know what constantly developing technology can do.

[ Is Hien being optimistic? Perhaps, but he's drawing a lot on past history here, and thinks it's logical enough for one's optimism to not be so blind after all. ]