X570 and B450 chipset motherboards are extremely hard to find in stock anywhere right now. Why? Intel chipset motherboards do not have same issues. Which raises legitimate concerns with upcoming B550 chipset -- will AMD and partners be able to keep up with demand? Would totally suck come June 16th and have same issue we are seeing now...
I have seen most on-line stores also listing B450 along with X570 and B550's with mid-June for availability. You might could say board makers no longer want to sell 400 series boards but AMD's announcement surprised them too so that makes no sense. And then what about the X570 boards? just as out of stock as B450. Why mid-June for all of them?
Really curious co-incidence...walking through a couple big-box stores picking up supplies I noticed
bicycles are also out of stock. Not the high-end graphite and aluminum frame ones, the inexpensive boardwalk cruisers and throw-away bikes kids get for summer vaca. Common thread: these bikes come from China too.
I think it's supply chain too. The west coast - LA, San Diego - the major US ports of entry for the inter-modal ships bringing those products in from China and California is tightly locked down in quarantine. I can imagine port traffic being incredibly delayed right now with very much slowed activity.
All you need is just one of those container ships to flood the market. It might be in a delayed arrival or even moored off-shore right now waiting to get in to be unloaded. If you hit EBay there are quite a few sellers of B450 boards shipping directly from China. The difference: air transport and prices well above MSRP.