Canakit, Element14 and RS all sell on Amazon, but that's fulfilled by Amazon and not purchased from Amazon. Some 3rd parties use Amazon fulfillment services, which offers some of the benefits (like free Prime shipping) but you are buying from a 3rd party and not Amazon directly. Considering how hard they are to find, and how far demand is exceeding supply, I would not expect to see any on Amazon for quite awhile (not for immediate shipment, anyway).
If you want a 2GB Pi 4B now, PiShop.us still has them in stock, and they ship fast (I ordered mine on the 4th and it was shipped on the 5th).
If you want a 1GB, Pimoroni has them. They're in the UK, but shipping is reasonable, and they don't ream you for VAT like PiHut does.
If you want a 4GB model ... learn to live with disappointment.
My mind is like a browser. 27 tabs are open, 9 aren't responding,
lots of pop-ups...and where is that annoying music coming from?