WHY DON'T bowling ball makers Make the bowling balls out of Shatter PROOF Plastic???

There are a LOT of other plastics that can be USED to make the lighter 6 to 12 lbs bowling balls out of that WILL NEVER chip like polyester always does so WHY the HEll don't the bowling ball Manufactures use those many other shatter PROOF plastics? LIKE: #1.polycarbonate, #2.Nylon, both are bullet PROOF plastics, #3.styren that's what the pins themselves are coated with = HIPS materiel: H= High I=Impact P=Poly S= Styren. #4. PETG, #5.poly olafins = A= UHMW, B HDPE & C LDPE. these are ALL harder then urethane: UHMW = Ultra High malcular weight, HDPE= High Denticy Poly Ethanolean & LDPE = Low Denticy Poly Ethanolean #6. ABS,
Ployeaster is more like a vary chip-able Acrlic glass type plastic. un-like all the plastics I list here!! vary shatter PROOF & will NEVER chip! 6 lbs of it would be so strong there is NO way it could chip no matter how many holes you dill into it or how fast its moving into even 5lb pins, remeber the pins themselves are coated with the HIPS materiel.