Public goods are typically provided by the state because they possess two key characteristics: non-excludability and non-rivalry. Non-excludability means that once the good is provided, it is difficult to exclude anyone from benefiting from it. Non-rivalry means that one person's use of the good does not diminish its availability for others.
Public goods are underprovided in the free market due to the free-rider problem. This occurs when individuals can benefit from the public good without contributing to its provision. Since people have no incentive to pay for something they can enjoy for free, private businesses may not have the motivation to produce public goods.
Therefore, state provision of public goods is necessary to ensure their provision and availability to everyone in society. Governments can use taxation and public funding to finance the production and maintenance of public goods, ensuring that they are accessible to all members of society.