The article states "lining costs almost as much as digging up and replacing the pipe", but that's only true if the pipes are only 4 feet under the pavement. In colder climates, this is not the case. Similarly, the problem of bacteria eating concrete pipe is more of a problem in warmer climates where the temperature of wastewater can be 20 deg C or higher, causing the bacteria to become extremely active. In colder climates, where it varies between 1 deg and 10 deg C, this is not the case.
All this being said, the article is making some grand claims that aren't globally applicable, and is lacking the detail required to properly understand the problem, yet jumps to a conclusion of "hey, wouldn't pre-biotics be a neat solution???". Ultimately, yes, and I understand that this is about researchers being excited about research, but we should try to focus on the present when addressing the problem of infrastructure that needs to be replaced immediately.