That article specifically discusses water filtration plants that are handling concentrated PFAS after filtering them away from drinking water. That the small fraction of them flowing through water treatment facilities can be broken down with special handling (which that article also says will not be ready for the market for some time) does not negate the fact that in the environment / our bodies, they are extremely slow to break down. I think it's obvious even to laypeople that the label is not literally true (nothing lasts forever), but it's still an apt descriptor. Even if municipal water can filter them out and break them down, these chemicals will be literally in our bodies and environments for the rest of our lives.