That answer you won't get from AMD when certain CPUs will be in stock again. Best to ask the Retailer themselves who might have some inside information about when a certain CPU or GPU will arrive at their store (ETA).
In fact even the Major Retailer might not know when they will be resupplied again.
Many Users here at AMD Forums are asking similar questions about when AMD's GPUs and CPUs will be back in supply again.
I found two Retailers that are selling the processor around $1400.00 but both are out-of-stock.
https://www.bhphotovideo.com/c/product/1516713-REG/amd_ryzen_threadripper_3960x_3_8.html
You can "CHAT" with them or call Customer Service to see if they can give you a date of when the processor will be available for sale.
https://www.adorama.com/AMD100110WOF.html?sterm=TD4wsn3IJxyLWyxwUx0Mo3YoUkEWoCU-I1QORM0&utm_source=r...
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Adorama, which is listed at PCPARTPICKER, you can ordered the processor and when available will be shipped out to you. (Can't verify if this Retailer is reliable or not).
Temporarily On Backorder
Although this item is temporarily on Backorder, you can order it now and it will ship as soon as it arrives. Your card will only be charged once item is shipped.
Notify me when in stock
Amazon and Newegg prices are around $300.00 more than $1400.00.