Continue Revenue Growth(say above 20%): It has to keep price low, lower than other stores which do not collect sales tax. So, the margin will be lower than before.
Flat or Shrinking revenue: to have health and reasonable margin(close to Costco or Walmart).
There is just no way to have high margin and high growth in the future because
* Its base is already too big to have growth.
* Consumers only have loyalty to the price. Won't like to pay higher price for the same products
What is the solution for Amazon ?
I think its CEO probably couldn't figure out and sold almost $200 million worth shares at the end of last year.