Amazon makes lot of money
There is no way you can get to $150B market vaue without earning money.
They have just been clever at dodging taxes around the world and move money into deparments with operating losses (aka heavy investments). so 150B/21Y ≃ 7B/Y. Not bad at all.
As long as the stockholders do not require dividends they can still keep the stock price high.
All multinationals have lots of advisors working on how to avoid taxes and give as little as possible back to the community. IBM probably have more financal acrobats than engineers.