I think there were probably times where software that got shipped actually worked. So you bought it and you could use it, no need for "maintenance". I generally don't think that's the right word since software doesn't decay on its own, so there's nothing to "maintain" actively. Apart from compatibility of course, but if that breaks (e.g. with newer OS or hardware), it would make sense to pay for an update if you need it. Makes a lot more sense than those disgusting subscription scams that adobe is pulling off (and every other company seems to follow).