What does that have to do with new owners / upgrading owners ratio? The last several months will be almost exclusively new purchasers. November will be primarily upgrades. The two don't correlate.
The correlation is that the Slim has lost all the sales from the core gamers/upgraders group because of the Pro.
If the Pro didn't exist I'm sure that more people in this group would be interested in buying a smaller, lighter, less noisy version of the console they own with 5 Ghz Wifi support as well.
But these people all know that something better is coming soon so they obviously prefer to wait for the other product.
The Xbox One S is benefiting of these upgraders buying the new system because it's smaller, adds a few 4K features right now, while Sony is seeing those sales delayed.
The Slim is indeed getting all its sales right now from new owners, but usually more price conscious consumers are now waiting for the holiday season deals and bundles.
And btw sales are still pretty close.