That is not logistically feasible, anon.
The post office has its own problems to deal with, not the least of which are its unions and its deals with companies like Amazon.
You think Amazon is paying to ship chinese fly-by-nights for free?
There is no way to make mail in voting secure. Not in time for this election cycle.
This is the last couple months of America as it used to exist. Whatever comes after will be something different, and depending upon how things go, it may require blood to secure an acceptable future state.