This is because Google has announced that both the Pixel 5 and the Pixel 4a 5G have been officially discontinued. Google’s decision is a bit odd because while the Pixel 4a 5G is replaced by the Pixel 5a 5G, the Pixel 5’s successor should be the Pixel 6, which should be announced in the coming month or two.
This means that discontinuing the Pixel 5 feels slightly premature on Google’s end, but we suppose that’s the current situation for now. That being said, while both phones are being discontinued, Google will continue to sell them and will continue to do so until they are out of stock.
Also, even if the company sells out, you will be able to find the phones from third-party retailers, but your luck may vary from retailer to retailer and how much inventory they have left, so you might want to move quickly if either phone appeals to you.