A failing drainage system can create a dangerously unhealthy, and totally unpleasant mess.
Replacement is expensive and disruptive.
Class action suits are in the courts. If all the pipe is bad you find one leak and them another and then cracked joints and broken joints that are not leaking. It kind of snowballs. I always look at brand just in case there is Phoenix which is the easiest to identify. I had one case last year in a 600-700 K home in Orinda that was mostly on a slab and had been redone in the 1980's.