We need something better than email.
Say everyone agrees and the entire world swaps to some alternative. Email 3.0 or whatever.
Wouldn't we just have the same issue? Any form of communication protocol (that can be self host able) will get abused by spam. Requiring a lot of extra work to manage.
As someone who does this, my main issue is now I am carrying around two phones. This is a daily annoyance for me.
My next round I think I am going to drop the work phone and use Androids profile options. Setup a work profile on my personal phone and just use that. Then just have work reimburse me for my personal phone/plan.