The fact that all of these services are based on OSS software is what will help keep Amazon in check as they continue to grow and dominate, because at the end of the day if AWS starts to turn into Oracle and get abusive with their pricing/licensing then the customer has a lot more leverage to move to another cloud or self host.
I am not holding my breath for some kind of government driven intervention, nor have I heard an idea of how that would work that makes sense. I think OSS is what is saving us here, and we should celebrate when a project becomes popular enough for AWS to offer it.
Is it fair to the developers that they don't get compensated, nope, but isn't part of the point of OSS to make sure that great solutions get reused and widely deployed?
I think companies building great software can continue to make money servicing it even with AWS in the picture, but I think if you want to make unicorn returns you are going to have to move further up the stack.
Honestly, at some point I hope we are no longer even taking about low level components like Kubernetes and Kafka and that we look back and laugh at the fact that we used to have to license and get support for these things individually. I do also hope that we manage to find a sustainable (if not equitable) model to support the development of these tools.
All the clouds are built on top of the Linux kernel and nobody really expects the kernel devs to get a cut of all those profits, but they seem to have a sustainable model for development, I hope we can continue to figure out good ways to do this for more and more OSS tools.