AMD’s Radeon RX 6800 series supply issues have been even worse than NVIDIA’s Ampere launch. Most retailers have received only double-digit AIB units with very few on the way. Unsurprisingly, this has jacked up the prices of the few parts still available on the market quite significantly.

We have had a private conversation with AMD. They assured us that in 4 to 8 weeks there will be AIB cards available at MSRP. They said they enabled the AIBs to achieve the 649 dollars [RX 6800 XT] MSRP and they expect that to happen within 8 weeks.
– Steve Walton, Hardware Unboxed
It looks like the situation won’t be changing in the next couple of months either. According to HardwareUnboxed, AMD has promised that the Big Navi AIB card prices should stabilize in the next 4-8 weeks, with the RX 6800 XT expected to return to its original price of $649 dollars by the beginning of 2021.
The supply problems aren’t really hard to figure out. A while back, it was discovered that AMD has allocated most of its 7nm supply to serve the next-gen Xbox Series X and PS5 consoles, leaving the remaining for the Ryzen 5000 CPUs and the least for the Navi 21 parts.