Note that Amazon.com has not proven it can profitably reinvest - just that it can reinvest and keep growing revenue. The question is why so many people believe Bezos when he said there was a plan to eventually become profitable.

(AWS is quite profitable, but retail isn't, and it doesn't have a moat.)

No, you are wrong about this. Or several years out of date at least. The idea that Amazon isn't profitable save for AWS is almost a meme for some reason in parts of the tech community, but it isn't true and never really has been when you account for re-investment.

Retail on its own has been profitable for several years now, and its margins are improving. Some of those numbers are public and some are not, but even with just the public numbers it is easy enough to infer the above. What's more, Amazon retail would be pretty wildly profitable, relative to the typical margins of retail, if Amazon stopped dumping billions of dollars every quarter into continuous expansion of its logistics capabilities. They're able to dump those billions while still pulling a slight profit. In general though, they optimize for free cash flow, not profit.

Source: worked there until recently

This was more about when Amazon was starting up (eg before Prime or slightly after it) than the last few years. Nobody expects it to die at this point. Also I said "quite profitable" not "profitable" ;)

> What's more, Amazon retail would be pretty wildly profitable, relative to the typical margins of retail, if Amazon stopped dumping billions of dollars every quarter into continuous expansion of its logistics capabilities.

Well, this is falsifiable, but it hasn't been tested, so I dunno.