Earlier quoted context omitted.
In practice, this means being able to run MacOS on them. All the hardware is already there, it's just a matter of time until Apple has the "courage" to enable it.
The issue is not courage. Apple knows that the use cases for the Macbook Air and the iPad Pro significantly overlap. So they use software limitations to avoid canibalising sells of one with the other even if it means making the iPad Pro a lesser product than it could be.
I'm not sure that's the case—Apple has generally not been afraid to cannibalize sales of their devices by their own devices.