system
A chat on subreddit /r/wallstreetbets
human
Micron doesn't do hbm manufacturing and amd will be using that for their gpu's that is done by sk hynix and Samsung. I wouldn't be bullish if you think amd roadmap will be better than nvidia.

gpt
If they go with HBM that's true, but any gaming PC build using a high end card will still need 16 or 32 GB of DDR4 and a new SSD. 
  
 Worst case, that's still lots of new sales opportunity.