Lightning is dead. USB-C seems to be where things are headed.
It is likely that Apple was a major influence on the USB Type C spec, so I assume that it meets Apple's form factor requirements. At the same time, Lightning is physically smaller, designed in, and there isn't any pressing need to change. It will happen, likely for the iPad Pro first, but the rest might be years away.
Lightning is not dead, not on life support, just aging gracefully. One could easily argue that all USB connectors other than Type C are dead as well, but they will be manufactured for years to come, and continue to be specified in many price sensitive products.