You're right. But can you imagine the patience of a power user to do that? They'd have to identify what the bug is, get the source, make the changes, test it,

You're right. But can you imagine the patience of a power user to do that? They'd have to identify what the bug is, get the source, make the changes, test it, build the OS for their own device, upload the fix to Gerrit for review, go through multiple rounds of code review, get it merged in. I've probably simplified some of those steps. You could do it, but would you? Remember, not every power user is a developer.