This makes it seem like it's just easy, but doesn't really say that for sure I guess: What if the bacteria become resistant to the phages too? Well, that

This makes it seem like it's just easy, but doesn't really say that for sure I guess: What if the bacteria become resistant to the phages too? Well, that can happen easily – probably even easier than with antibiotics. Cells have been duking it out with viruses since the beginning of life. (Did you know CRISPR-Cas9, now used for gene editing, evolved in nature as a way for bacteria to recognize and cut up phage DNA?) But the difference is that whereas new antibiotics are very hard to find, there is a nigh-inexhaustible evolutionary font of phages constantly pulling ahead in the arms race. So in short: once a bacteria becomes resistant to your special phage, just find a new phage.