Thank you for bringing this to our attention. Unfortunately, this is no longer something we intend to work on, and the documentation has been updated accordingly.
We have a use case for draft order subscriptions and I wanted to share it.
We close sales offline via a call center. We can currently do this with ReCharge subscriptions via the ReCharge Checkout API. Not being able to create and close draft order subscriptions for our customers is certainly a shortcoming for us with the native Shopify Subscriptions API.