Earlier quoted context omitted.
I've toured a couple of ATC towers recently and my impression was they were surprisingly low tech. A tech upgrade seems like the most viable solution at this point. There are processes for writing and testing software and hardware for environments such as this, but the government needs to be willing to make the investment.
The government is making that investment. Upgrading the legacy system will take decades regardless of how much money they spend. https://www.faa.gov/nextgen
The first proposal to break out the regulation of air traffic control with the provision of the air traffic control was done by the Clinton administration. Support since then has been bipartisan and opposition has also been from members of both parties for various reasons. (I read somewhere that one of the biggest long time opponents of breaking out the air traffic control has been the associations of owners of private jets as they currently pay about 1% of the cost of ATC, but are closer to 10% of the flights in major airports. In reality, owners of private jets can likely afford to pay a more proportional percentage of the costs they impose on the system.)