In short it's because of this one word "Address".
Just like your home in the real world there is an "Address" associated with it in order for society to communicate with you among many other reasons. (excluding Jerimia Johnson types).
We don't associate our identies by ISP's, Cities, real addresses, etc. Can you even have any social media account (Twitter, Facebook) without an email address?
IDK? It may not be dead technology but it's in hibernation mode.