That being said, I'm trying to get us to open source the "base" version which is provided to OEMs.
Can I assume you're involved with KaiOS development? Android vendors have a terrible reputation about pushing security updates in a timely manner (or at all for devices that aren't the current flagship). Do you have any plans to contractually force or otherwise encourage vendors to push security updates?
That's a bit disingenous. Android wasn't shipping anything and it always released sources, as far as I know. Same for almost any Linux distribution out there. Common courtesy calls for distributing at least "release" versions, like RedHat and even Apple do.
That, to me, sounds like you're currently taking the minimalist "we'll release the bare minimum we are legally forced to, and nothing else" stance, which is basically equivalent to "we are not going to give back anything if we can avoid it".
I do hope this will change in the future, although given the realities of embedded development (cut-throat and all), I wouldn't be surprised if it never did. I think I'll keep rooting for more open players in the space.
There was this project for FirefoxOS to support J2ME apps -- https://github.com/mozilla/pluotsorbet It would be great to have something like that for "nostalgic" reasons. Many feature phones' users remember J2ME apps, games especially, very fondly. Check out also this J2ME project, which could potentially be ported to KaiOS as well: https://github.com/XerTheSquirrel/SquirrelJME
Also, have you considered some kind of support for "content blocking" (like in iOS, or in the form of typical browser plugin-ins), of course, I'm not saying that ANY content should be blocked by default. But taking into account that devices with KaiOS wouldn't be very powerful, it could be really useful to have such an option to avoid "unnecessary" stuff when browsing the Internet...
Anyway, keep up good work!
If you don't make it open source, that challenge will be levied at every opportunity, and rightly so.