This is not in the developers interests usually. I have heard release exclusives but they all almost have expiration dates.
> Their way gives the power to the user. The user copies across iOS app binary and system libraries and it's done.
While it may empower users, it's not widely practical. (IANAL) You also have a problem that it's near impossible to get the apps off the device (you can download them with iTunes on the desktop though), then you have to decrypt them of their FairPlay encryption, and then transfer them to an Android device without possibly violating several licenses, the DMCA, and few copyrights along the way.
Providing an SDK for developers to cross compile their apps means that the apps are built and optimized specifically for Android when compiled and the distribution is not an issue for the developers because it's just like any other app on Android. It also allows the developer to integrate and provide support for system features specifically on Android.
> They don't need to be commercially viable because they're a research project.
It's not that it's not commercially viable but that highly impractical. It's will be hard to distribute and make very accessible and usable for users.