Big/old companies tend to get entrenched in their ways, I see this everywhere as a MSP, spouting idioms like "If it ain't broke don't fix it!" and "There's no need to reinvent the wheel".
It was a medical device manufacturer, so it wasn't just company inertia holding them back - any change had to go through regulatory compliance. The company was in the midst of replacing their planning and tracking system when I left, and they've changed ownership twice, so I presume they've managed to replace those old systems too. I shudder to think of the problems they're having if they haven't.