Interesting that you went to profit immediately. Much of my use of OSS is personal and for fun and because I believe it makes the world a better place that I can run things like Linux and postgres and get so much out of my computer that would never be possible if I had to pay for all of this. Furthermore, I don't like doing things many different ways, because it's a waste of time and energy, so I try to bring my experience with me when I work somewhere. And I give back in the form of my own free and generously licensed software contributions.
Akka may have been steered by a group of people incentivised financially to support it, through support agreements or whatever, but it currently has 774 contributors. And frankly, never would have become what it is if it started closed source. Probably wouldn't have gotten off the ground honestly, as something open source would have eaten its lunch. I don't use it, but the idea that I can use something anywhere in perpetuity is part of why I choose to use and give back to FOSS. Many feel the same.
Sure. Anybody can fork the software and maintain it. I love that OpenSearch did exactly that when Elastic decided it wanted money for something built on the efforts of a community. But I also know that forks are another waste of energy. Maintaining two branches that do similar things is silly if I can let you do your job while I do mine. I'm not maintaining my own OS, or my own database, or my own terminal, etc etc. Add to that, how many individuals would be willing to fork when one branch has demonstrated a willingness to make choices in favor of money? It makes me wonder if they'll also push for patents or law suits against those who might add features to Akka Prime or some cleverly named fork.
Frankly, I don't use Akka and I'm definitely not going to now, so as far as I'm concerned, Akka is more than welcome to sign their own death warrant. But this trend of building software with community contributions and then trying to profit from it is worrisome and frankly, pretty close to theft. I don't see any of these companies retroactively paying their contributors, so it's definitely not about "what's right." It's a cash grab branded as sustainability, and it has a chilling effect for me, that pushes against the ideals of OSS.