Amazon is planning to hire another 20,000 people in Seattle within 3 years, on top of the 40,000 they currently have there. Then another 50,000 HQ office worker

Amazon is planning to hire another 20,000 people in Seattle within 3 years, on top of the 40,000 they currently have there. Then another 50,000 HQ office workers at HQ2, so overall HQ staff is expected double within 5-10 years. (Even if some of the Seattle headcount shifts to HQ2, it'll still be close to a doubling.) It's mind boggling to me that they foresee their HQ staff doubling; I lack the imagination to guess what all those people are going to be doing. Aside from physical retail, what markets might they be eyeing?