Anyway, Amazon is still the underdog going up against Walmart which twenty years on has really good technical chops and turns over a lot more goods and has phenomenally good logistics...think about who is going to benefit more from autonymous trucks. While it has the overhead of a vehicle fleet it is not at the mercy of UPS and Fedex and for a lot of goods, ordering online and picking up at the local Walmart is about as good as door to door shipping.
Anyway, in some ways Netflix is more likely to be crushed by Walmart than Amazon...and Disney is even more likely than either of them. As internet purchases and bandwidth increasingly become commodities, companies with long horizons become more formidable particularly in markets that matter...the players in the mobile market are Deutsch Telecom and ATT not plucky entrepreneurs. The big car makers are moving on self-driving cars and they already have down the really hard part of making cars...software can be copied.
The infinite pie theory is for all practical purposes impossible. Growing pie theory works on beyond lifetime scale, but not for decade level scale. So it does matter because a startup can't last for two decades to try and gain market share against an incumbent.