Destiny is not a full blown MMORPG, but is is a looter shooter that falls into the MMO style of games similar to something like Borderlands and The Division. These types of games are more than just a PVE campaign with a PVP playlist, they are games where you make and build a character over time. In a COD game, you expect to complete the campaign in less than 12 hours then spend the rest of the time in PVP. In Destiny, there is no clear endpoint. If your endpoint is completing the campaign, sure, it only takes about 2 hours to do the Shadowkeep campaign, but if your endpoint is getting to max power, or getting full raid gear, or getting Seasonal Titles, then you should expect to be playing for hundreds of hours. That being said, yes, I don't think you should expect to have everything obtained in a week. If you think you should have everything in a week, let me point you in the direction of a game like COD.