Amazons retail business is doing just fine. Grew 20% YoY, give or take, for years. Is cash positive, basically all the time. And the last bit, positive cash flow, is so hard to achieve.
Cash flow is obviously important to you, but note that business profitability involves having positive cash flow and making a profit on it. It would be perfectly reasonable to discover in a few years that Amazon is structurally unable to make a profit without giving competitors an easy path to start cannibalising their business.
It is an uncertain scenario at the moment because it does look like Amazon will be one of the rare attempts that can find profits. But they haven't managed to outdo Walmart yet so there are obvious risks.
Positive Cash flow is what makes a company default alive, so it is important to everyone. Peofiability, EBITDA and ao on, live on a different axis. A company can easily be cash negative and profitable or cash positive and loosing money. The latter one is in a better position, a company that is both, profitable and cash positive, is in a great position (e.g. Amazon), one that is neither is actually dead.
It is an uncertain scenario at the moment because it does look like Amazon will be one of the rare attempts that can find profits. But they haven't managed to outdo Walmart yet so there are obvious risks.