Half of the problem with cash could be solved by ending the war on drugs. The war on drugs has created a class of people whose main economic function is to transfer wealth from the public to the worst people in society. This is a many-headed monster that robs/burglarizes/steals money from average people, and vacuums it into a global system of money laundering. The cost is mostly absorbed through higher insurance premiums and more costly welfare schemes. The physical needs of this class of people are often carried by family and charity.
No cash could kill this, but so could treating drugs like simple agricultural and/or chemical products and regulate the distribution.
All costs of the war on drugs are covered by the public. All profit by heavy criminals.
Sort this first, and then get back to cash and its utility in evading taxes.