I suspect Doc is right that too many people haven’t changed their belts and wind up stranded with a car that’s needing a new engine and one too many people complaining to the manufacturer about it; never mind they couldn’t tell you where the maintenance schedule/owner’s manual is in the car and they’ve owned the car since new.
Another thing is that many owners will be told they need to change their timing belt on their car, then get told it’s $500-1000+, then they trade the car in so they don’t have to spend “all that money”