Plus, the way it was written was the way ppl spoke at that time. Since then, the English language has changed, and no one uses 'eth' at the end of their words. If they do, and they are not quoting a Shakespeare play, they need committed.
The newer versions are written the way we speak today. I'd imagine that if time lasts a lot longer, the English language will sound different than it does now, ergo, newer versions with updated language being published. Its called keeping up with the times.