It was a lot more than that. They developed systems and techniques that even Amazon adopted and are still adopting to this day. They also created a ton of open source tools for other people to use the cloud:

https://netflix.github.io

Netflix tech even spawned a company to sell their open source tools:

https://www.armory.io

And they codified the entire practice of Chaos Engineering:

https://en.wikipedia.org/wiki/Chaos_engineering