I am real mad about the Elastic relicense so I'm going to vent a bit.
Say that I contributed some code to Elastic, under the original open source license. That license defines the terms of our engagement. Me: "hey I improved your code, can you include this fix so I and everyone can use it?" Elastic: "sure!"
They require a CLA, which assigns ownership of my fix to the project steward. The idealistic reason to do this is to protect the long-term health of the project: if copyright law gets totally rewritten, we can update the license to reflect our original intent!
But this also requires me to trust in the steward organization to do the right thing. As the copyright holder on the project, I gave them the power to update the license to *anything* they want. Which, in this case, Elastic did.
Elastic didn't pick another open source license, which would provide the same guarantees for how I can use, contribute to, and redistribute the software. No, instead they said "thanks for contributing, your code is proprietary now, f off so we can make more money"