...apart from AMD perhaps wanting to see a.) Ryzen 3000 actual sales uptakes, especially for the late fall and holiday season, and b.) having (potentially) up to 16c/32t in the 'regular/non-TR' config Ryzen 3000, perhaps for a phased release, and c.) see what Intel brings to the table in response to the Ryzen 3000 release and review hoopla...there's the Epyc server chip issue also touched on above.
AFAIK, Threadripper and upper level-Epyc cores are binned chiplets, and the real money and profit is in data centers...Amazon, for example, just announced an expansion of their Epyc-based server base. I do not know what the yields will be on the new 7nm process, but if Amazon and other big firms actually pave the way for more Epyc market share in data centers, AMD is sure to service that first, given that they once before seemed to abandon the server market and don't want to do that again. So if Epyc 7nm pre-orders are indeed rolling in, Threadripper for consumers might be pushed back a bit. Then again, all this is till idle speculation until Computex and related AMD presentations have taken place.