Amazon is on low margin retail business. Amazons market cap is $475B. Assuming 10% ROI and 3% profit margin, Amazon must make $16 trillion in revenue some time in the future to justify the current price.
US retail sales are $5 trillion.
Total retail sales across the globe are $22 trillion.
Even if Amazon continues to grow at current pace, it runs out of markets to dominate before current stock price can be justified.
Bezos announced that he is unloading $1B per year. Smart man this Bezos guy.