Some people would say that the legacy that Apple has left is products like the iPhone, Mac or the Apple II etc. These are merely products and products wax and wane and eventually are resigned to the annals of history.
One thing that is greatly overlooked by many is the products that are software based and the biggest product that is really flying under the radar is their programming language Swift.
It’s become the language favored by Apple app developers, Apple has not merely released it and then moved on but have even developed an app for iPad’s to make learning the basic’s of Swift fun to learn for children. I’ve played with Swift Playgrounds and it is so engrossing that I’ve lost track of time. I’ve heard of children that have had fun learning in a similar manner, these are the same kids that love Minecraft.
It’s not that this that would make it a legacy, not the adoption rate of the language, not the way that children use it but the fact that IBM have adopted it as their server language of choice.
Apple were smart, they didn’t restrict it to just Apple products or development of apps they made the source available so that it could be used to develop for Android, Windows, Linux etc.
This is a true legacy, something that if Apple was to cease operating would still live on.