Because if GDP per capita increases cost for services as well as number of required services increases.
Take a car analogy, if the GDP per capita increases such that the number of people who can afford a car doubles, the government will have to invest more in roads. Moreover the expectations to the quality of the roads will likely increase as well. In other words if more stuff gets done in a country your more likely to night more infrastructure and services to support it.
Take a car analogy, if the GDP per capita increases such that the number of people who can afford a car doubles, the government will have to invest more in roads. Moreover the expectations to the quality of the roads will likely increase as well. In other words if more stuff gets done in a country your more likely to night more infrastructure and services to support it.