I'm not sure what point you are trying to make. If you look at most of the high profile hacks and leaks in the past 20 years, very few of them are from web 2.0 tech companies (e.g. Google, Facebook) rather than dinosaurs (ex. Target). Those that have (like Google) have only been successfully breached by nation actors (e.g. China, NSA).

As far as I can tell, there's no data to back up the assertion that these large tech companies are disregarding security if favor of profits, except for Twitch now, which is why this leak is interesting to me.

> In my experience with corporations there is little to no technical sharing between different parts of the company.

Amazon is all about sharing efforts with the company. That's the whole point of AWS - its a monetization of this efforts. Most older AWS services started out as internal services that someone realized was generally useful.