Yep. This is the problem. If I switch platforms, I have to start all over. If I stick with Google/iPhone, I just log into my account on the latest and greatest device, and voilà, all my stuff populates on the screen. Apps, conversations, albums, playlists, etc.

I don't think there is an obvious way to legislate against this short of banning this feature, which is probably worse than the status quo.