I'm really confused by your perspective. How is this a win for open source? A big open source project has just shifted away from open source to protect their revenue stream, and now serves as (yet another) warning against other companies to open source their code because Amazon will eat your lunch.

No matter what you believe is right I fail to see how events such as this are anything but bad for open source. This will directly lead to fewer companies working on open source code, fewer jobs available writing open source code, and fewer code being available outside of the closed-source moats of tech giants for smaller companies to use.