This is false actually; there's really no hope because you can't get the city running smoothly without massive redesigning because the new service buildings do not support the same capacity as the old ones. So even if you fully upgrade everything, you'll have to tear down buildings because there won't be enough coverage for them all. Or you could try to have duplicate service buildings but, I found that it doesn't really work and is super buggy, they don't overlap to distribute service evenly and it constantly shows buildings without service even though the service is available. I spent a week attempting to resolve even one region and found no possible way, even a new section I started from scratch I could not get functioning properly. I gave up and joined the mass exodus as the game is now unplayable.