The issue is Amazon stock is very expensive when compared with other companies. Walmart's market cap is ~250B, whereas Amazon is $350B. Amazon had $100B sales

The issue is Amazon stock is very expensive when compared with other companies. Walmart's market cap is ~250B, whereas Amazon is $350B. Amazon had $100B sales last year, Walmart had $500B. If Amazon can generate profit at the same rate as Walmart then Amazon needs to get to $700B in sales for that valuation to make sense... If Amazon double's in value again it would have to have sales representing 10% of US GDP at the same profitability level as Walmart. Smells like a speculative bubble to me.