If I have $0.50 cash and someone reaches into my wallet and takes it, is that any different to if I've got a lottery ticket with an expected value of $0.50, and the draw occurs and its value drops to $0 when it doesn't win?
Some would say that in the first case it's morally wrong to steal my cash, whereas in the latter case I consented to the risk of my ticket losing when I purchased it; and therefore performing a lottery draw is not an immoral act.
Yes, if the Amazon model doesn't work out and you lose value, that's not immoral. It just happened like your lottery. If the value decreases from people stealing from Amazon then it is the same as going in your wallet and taking the cash.
Some would say that in the first case it's morally wrong to steal my cash, whereas in the latter case I consented to the risk of my ticket losing when I purchased it; and therefore performing a lottery draw is not an immoral act.