i think you see this rarely discussed because its an issue that is rapidly declining in importance over time.

The trade off of either-this-US-kid-gets-it-or-that-Indian-adult-gets-it becomes less severe when availability of vaccines is going up everywhere rapidly.

Where vaccine availability is low, its not due to US hoarding but rather due to regional government policy constraints that wouldn't be alleviated if this-US-kid gave up their dose.

so, scarcity is certainly the case sometimes (like right now for Paxlovid) but not for general availability vaccines worldwide.