Tom's Hardware reached out to AMD and Intel. The former hasn't responded yet but Intel claims they're working to bring back support.
We reached out to Intel for comment, and the company provided the following brief statement to Tom's Hardware:
"We are working to bring back Radeon graphics driver support to Intel NUC 8 Extreme Mini PCs (previously codenamed “Hades Canyon”)."
We've inquired with AMD on the matter, too, but have yet to receive an official statement on when, and if, the company will provide support again for the Radeon RX Vega graphics units in the Kaby Lake-G chips.