Step 1: Apple introduced the iPad and everybody was desperate to get one because it was the trendy item to have.
Step 2: people started figuring out what they could do with a handy portable computer.
Step 3: everybody who had a use for a tablet had one and the sales dropped off to replacement level.
Any remotely interesting new product is going to grow at unsustainable levels until the market is saturated. Then the growth stops.