There are few things which, when property rights are properly allocated, private citizens can't manage themselves. But most of the 'easier wins' in this area have been achieved. The complex ones remain.
For instance, privatisation of roads is possible theoretically, but practically has been very challenging to implement. New land records technologies that permit tiny parcels of land to be registered and traded can allow privatisation of the kerb for bus stops (I've discussed this earlier) but also road lanes.
Unfortunately, governments will remain reluctant to transfer property rights back to the people even though they can do so (under regulatory control), since governments are a monopoly and suffer an extreme form of inertia.
So what can be done to reduce the role of government? This would involve finding ways to short-circuit government itself. Many public goods/ collective choice problems are coordination and/or reputation management problems that could (with a lot of thinking) be broken down into component parts and resolved technologically. It is these coordination/reputation problems that led to the demand for government in the first place. We can get rid of such demand and help shrink government.
Government provided/managed public transport could become irrelevant as "super-uber" type applications that have mastered identity and reputation management, as well as pricing and auction models, allow thick markets in transport.
This could, for instance, involve algorithms that automatically calculate the best person to hitch a ride, with certified riders and drivers on both sides. I could type into the app that I want to go from A to B – and will pay $5 – and someone who meets the algorithm could get a signal (if he is open to that signal and driving that way), decide he wants an additional $5 and a SAFE rider, and pick me up in one minute, since he was nearby. It would involve linking with GPS and an identity and reputation management system – plus an auction model (so if I'm in a hurry I could offer $10).
[Someone has informed me that such a thing is already in operation: https://www.folksvagn.com/]
SCHOOL AND COLLEGE EDUCATION
This app would allow approved individual teachers to directly (and individually) teach students from across the world (each of whom could change each day, depending on what a person is doing). So if an app agrees to a syllabus and approves thousands of teachers then students could, based on their availability, tap into whichever teacher is teaching at that moment (each teacher being limited to 20 students at a time, say), thereby completing their course work with total flexibility. Payment would be by bitcoin etc. per lecture/tutorial, and approved teachers would also hold course exams on demand (i.e. as mutually convenient). This would eliminate the need for any government role in education, even if the government wants to have a role.
This is different from MOOCs etc. in the sense it is interactive and involves direct teaching by a human. Would be particularly useful for standardised school courses and bachelors degree courses, and would allow voluntary teachers from across the world to teach individual children.
If people can cheaply agree to reliable private justice systems (assisted by technology such as robotics) they could resolve their justice issues (particularly civil matters) without access to the government justice system.
Innovations like Bitcoin can eliminate both banking and central banking. [There are huge risks to Bitcoin at this stage, but I think it does illustrate the general principle].