I think that’s due to the quality of poly offered when that was installed. I’ve run a lot of poly, my dad has run a lot more than a lot, and have never been back to make a repair. We use socket fusion and mechanical fittings.We had a 3/4” Black Polyethylene waterline 340’ from our well to the house in Pittsburg Co. from 1977 to around 1998. I can’t remember a winter without at least a couple of splits in it. We put in PEX from the submersible pump all the way to the house….. no problems since.