[fpgeek]

I think you're missing large parts of Amazon's consumer-facing value.

First and foremost, they have Kindle. To a first approximation this means that "everyone" who reads ebooks uses part of their ecosystem (even people who mostly read on other platforms use Kindle for exclusives, past purchases, etc.). And that fortress has only grown with Comixology and Audible. All of which are still DRMed, so the platform lock-in is huge.

Second, I think you've missed the unique selling point of Prime Video. It's not just a crappy Netflix ripoff or an iTunes ripoff, it is the only platform that seamlessly integrates subscribed videos and purchased videos. So, for example, done with the free Season 1, but Season 2 is in the middle of its initial broadcast? You can catch up by buying the episodes you missed. Grumpy that something dropped out of Prime Video lineup? You can buy that too. And so on. My understanding is that this partially extends to add-on cable channels, but I haven't actually tried that.

Third, they have the same seamless subscription and purchased mix with digital music. That isn't as special as Prime Video because Google and Apple have that mix too and the triumph of DRM-free music makes platform-switching much less painful. To the extent that Amazon has a special advantage here (AutoRip), that does depend on the retail core.

I think you dramatically underestimate the advantages Amazon has. If Walmart et al go in for the kill, I would not like their odds.