Unfortunately, I think you are wrong on this issue. IF UA was making space available on their own metal, then I would agree with you.

In reality, the bulk of the availability on intl flights is on partners....especially to Asia and Africa.

What that means IMO, is that UA is using partners as a clearinghouse for highly expensive (in miles) award seats...very similar to how AA is driving award redemptions to BA where they collect absurd YQ often just short of revenue ticket costs (combining cost of miles plus YQ).

And if I am correct, we will see more and more tightening of UA premium award inventory, which will force anyone looking to redeeming for premium cabins to either spend drastically more or to fly Y, which will tighten availability for Y savers on partners.

Let us all hope I am wrong...