[rdedev]

The reason I explained in my previous comment deals with the interaction between our body and the phage. A lot of drugs fail in this phase. What works in a cell culture need not work in the body. Even if you find the right phase for your infection it still might not work. All this might be solved with genetic engineering. But there a lot of work to do.

Also as an aside, physics is easier than biology. Once you figure out a solution that works, it always works in the future. The moon is not actively changing its orbit to survive. Bacteria or cancer for that matter always end up finding a way to overcome