I would argue the income tax issue
is that simple. The bet Amazon made was that profits didn't define the valuation of the business. The part that wasn't black & white was that folks were split on whether he was a genius or a scam artist running a book retailer with a 400+ p/e ratio.
Gaming the system is what I'd call their sales tax treatment. They didn't collect it everywhere until they got so large that they're warehouses and datacenters were everywhere. And depending on jurisdiction I think its the 3rd party sellers' responsibility where possible.