That would be a fundamental change to how Git works, not just GitHub. Even if the web UI didn't show it, a simple `git log` would reveal it.

You can mask your email address in git commits but a lot of open source projects won't accept that. And some pseudo-open-source ones insist on sending you an email to authenticate before they'll give you access to the GitHub repo (looking at you Unreal Engine!)

So, no, I don't think they could simply "not show the email address".