Amazon works coniniously to become the provider for everything you can imagine
Amazon may have some cheap prices and their customer service has the margins available to offer refunds/replacements quickly. But that all is easy guise. Amazon is rotten inside. Each product team does whatever it wants. So how long can the exterior hold a toxic spill?
Those AWS dashboard icons look really nice. Makes everything look so organized and contiguous. But each of those services is done in different languages, different frameworks, by different teams, with whatever crap will hold the leaks and terrible patchwork programming by their average employee who will on average, stay less than a year. The churn is real.
It's one of the core paradoxes of economics. I want a cushy job with great pay, but when I go shopping I implicitly want everyone else to have a shitty job with low pay. There's a name for this paradox but I'm forgetting it right now.
It's very similar to the paradox of thrift: it's in my interest to save, but for me to save someone else must be spending. If everyone saves nobody can save.
Almost everything in economics is a paradox since there are two columns in accounting-- every transaction has a counter-party. It's bizarre for something not to be a paradox in economics.
If everyone has the same capabilities and preferences, then the economy is a zero-sum game like you've described. In some fields, that's close to true, and those fields tend to be low-margin commodities.
Why do 27k engineers (in Seattle alone) need to write in the same language to make a service successful? How many SAAS startups have you worked at? How does Amazon/AWS compare to this? I think you're out of touch and/or lacking context.