As you may know Public transport is for free in Luxembourg, admittedly it is a very small country, but no controllers, no selling of tickets, no ticket machines (anymore).Hungary is much much bigger, but for society and human interaction it might be good to follow.
Would be good a balance to make between cost and revenues. (Of course many people will lose their job, but some of them can go to the police and catch vandals I think).
Admittedly public transport is cheap, but removing bureaucracy would be good I think.