Above all, they've found a good pricing policy to monetize the thing properly, while offering decent fanservice. Sometimes the DLC policy annoys me, too, but in the end I just know that you hardly survive otherwise today, if you serve such a niche market.
@Staatsmann I don't think the DLCs are that bad, I didn't buy them all, but only the ones that interested me, and then mostly only on offer. They were relatively cheap to buy and mMn a fair price.