The AWS model isn't that they actually do novel development on this software, it's that they grab the code, add a bunch of crufty hacks to it to make it work better in their environment then sell it as a hosted version.

Think of it like the Amazon marketplace equivalent: watch for products doing well, then get the cheapest possible clone made and sell it as Amazon Basic, while harassing the original vendors of these products and promoting their own brand in search results.