Amazon, even with its huge warehouses, doesn't directly stock everything. If you look closely, much of their merchandise is sold via 3rd party suppliers, and Amazon just acts as a "conduit"....in which case you have to wait for that supplier to do the transaction.
Personally, I usually check Amazon when I am buying something online...and then I check EBAY, and several other online sources. Invariably, I go with EBAY or one of the other suppliers, and get the item for substantially less than Amazon would charge. Amazon is usually a better buy than most traditional retail outlets, but a few keyboard strokes usually finds a better buy than Amazon...at least, that has been my experience.
Yes, I also shop the keyboard..
The items that I ordered stated "fulfilled by Amazon"..