Just because you have the source code to Android doesn't mean you have a fully-open phone or operating system. Your Android apps are still limited to their Java sandbox, and you still don't necessarily have any sort of access to tinker with the OS installed on your phone, let alone re-flash it at will like I can with my Neo.
If I screw something up, or if I one day decide I want to run Debian Linux instead of Angstrom/Openmoko, I'm free to reflash my phone's bootloader, kernel, and rootfs, or specially format its Micro SD card and boot from that instead. With Android, you don't yet have any of that freedom, and if the American cellular companies have anything to say about, you never will.
However, I will grant you the fact that Google has a gigantically higher chance of changing the face of mobile communications with Android than Openmoko, but I'd still rather have my Neo any day.
I'd say it's an open question. It depends on the hardware manufacturers and carriers and what they let you do, and at this point it's anyone's guess as to what will be allowed where. Initially we probably won't see "anything goes" types of deals, but maybe we will later on. Once you get sources though... I don't think it'll be long before people start doing C-based stuff. The Java environment (which isn't really Java in terms of the VM) is so that they can keep some semblance of control for non-hacker type people.
If I screw something up, or if I one day decide I want to run Debian Linux instead of Angstrom/Openmoko, I'm free to reflash my phone's bootloader, kernel, and rootfs, or specially format its Micro SD card and boot from that instead. With Android, you don't yet have any of that freedom, and if the American cellular companies have anything to say about, you never will.
However, I will grant you the fact that Google has a gigantically higher chance of changing the face of mobile communications with Android than Openmoko, but I'd still rather have my Neo any day.