Why is it difficult to finance public goods compared to private goods?

Public goods are difficult to finance compared to private goods because they are non-excludable and non-rivalrous. This means that it is difficult to charge people for the use of public goods, as anyone can access them without paying. Additionally, the consumption of public goods by one person does not reduce the amount available for others, so it is difficult to charge people for the use of them. This makes it difficult to generate revenue to finance public goods.