Quoted from Whysnow:Why would these 2 companies not explore this potential alternative and the benefits that could come?
Because it would take a whole lot of time and money to develop a new board set. The P3-ROC is pretty cheap now because they make a lot of them:
https://www.multimorphic.com/store/circuit-boards/p3-roc/
Manufacturer's get big discounts because they order in quantity. It's good for the customer if manufacturers use a universal board because they customers can swap parts between different games and even different companies' games to troubleshoot and keep them running.