[NathanKP]

Disclosure: I work at AWS and this is my personal opinion.

I've seen growing levels of AWS contribution back to upstream projects over the past four years. Teams start out by operating a piece of software at scale, whether it is Redis, Kubernetes, etc. After they have operated it for a while they discover the bugs or performance issues, or customers of the service complain about something. At that point the team now has enough real world experience with that software to begin to contribute back to upstream.

It takes time: to learn the ins and outs of the software well enough to know where and what improvements should be made, to understand the software's design and history well enough not to make bad suggestions or contributions that were already determined to be dead ends in the past, and to earn the approval of the community and existing maintainers enough to get significant contributions accepted in the first place.