Why does it have to be new? Plenty of open source OSes exist... starting with Android! GrapheneOS is based on AOSP, you would call it Android. If I show you a phone running GrapheneOS, you probably won't even realise that it's running an alternative OS: it will be Android to you.
The problem is not that we don't have alternative. The problem is that Google is moving towards forcing everyone to run their OS (or the OSes they accept, since it includes iOS) to connect to random stuff on the Internet. They are literally building technology that will prevent alternative OSes from running properly.
No need to create new OSes if anyway they won't work, right?
That's the reason companies are desperate to be first/biggest - once you're it, you're it until you finally fall on your face and dwindle to a nobody.
The thing here is that Google is building technology to prevent alternatives from connecting at all. We fundamentally cannot solve it by building more alternatives, we have to prevent Google (and TooBigTech in general) from doing it.
at my most pessimistic i can see a world where consumers pay MORE for attestation to continue to opt-in to society, or perhaps a ai-bot-free digital world.
Your privacy is dead, and you cannot do anything against it, except not using phones and internet... at all. I mean I still fight against it, but not by protecting my privacy by using tools, or using different tools, because I realized it's not possible. There is no "as less data as possible". They know regardless.
I used VPN, browser containers for everything, myriad of fingerprinting protection, nothing related to Google/Facebook/etc. And then I went up to Youtube once for something, and they knew exactly what were my thoughts at the time. That was the moment when I realized that I suffered for nothing.
I still support for privacy movements, and I strongly believe that the only place where we can do anything at this point is politics. You can't protect your privacy anymore at this current environment, that ship sailed decades ago.
My problem is that basically every larger for privacy push is against newly proposed laws (like age verification), and there is basically no large uproar regarding the current already fucked up laws.