CPDLC is being used for only 5%
This is the first step and US governance just passed a law to fund ADS-B progression big time, a part of it was to allow UAV's into domestic controlled class B airspace. Never, really? Follow the money trail, capitalism is a monster that wants this! It is not a question of if, is is one of when! All the rest of your points are subject to a solution, modernization will find the answers.