The vast majority of those generic tablets retail for under $60 and many of them are not even capable of connecting to the internet. They are at best considered children's toys. They run Android, but do not connect to the Android Play Store. They come loaded with a few built-in games, but you cannot add any more. Many others are like this one, running a very old version of Android:
Apad s3c64100 667Hz 256MB/2GB 7-inch MID Touchpad
Yes, that one is for sale today and was made in 2015 . . . but the companies who total these sales count them as competing with Apple's top of the line iPads as though they were the same market. They are not. People buy them and when they find they are pretty much useless, toss them in a drawer and forget about them. Look around. Do you ever see anyone using one?