I don't subscribe to this theory (and I used to work in the oil industry).
Mileage matters, time doesn't. High mileage is obvious. Low mileage is bad if the engine isn't brought up to operating temperature so that some of the 'undesireables' (that got in the oil during start up) can gas/flash off.
Worst case is the people who start the car once a month during the winter and let it run for just a couple of minutes.
JMHO, I know others will have other opinions.
