They already hooked a few million people. Mission accomplished. These ppl will buy each and every DLC regardless. Then you cater to the casual crowd which they’ve done with D2 and you sell even more. They make all their money in lumps during DLC cycles so it doesn’t matter if people actively play or not. 3 times per year they’re making hundreds of millions of dollars for very little work. Then you add a $hit ton more money from cash shop transactions as the cherry on top.