Megiddo on 04 April 2018
Perhaps because Amazon is a massive online retailer which serves the entire country of Japan and that is only one Yodobashi Camera store and is completely useless in determining the large-scale inventory available for a console.
Have a look yourself: https://www.yodobashi.com/?word=Switch
The green "在庫あり" means it's in stock.
Also, just for fun. https://www.yodobashi.com/?word=PS4
The red "お取り寄せ" means it's out of stock.
