The cost of extending the period of compulsory education is just too high. The increase in numbers would require a huge investment in teachers, books, new school buildings, computers, etc. As well as these direct costs there is also a huge amount of losses that a country would face. Young people who leave school and enter the workforce contribute to the economy through taxes and contributions to pensions which the country would no longer receive if people remained in school. It is impossible to spend more while also earning less. This means that raising the school leaving age is not something that countries can afford to do because they won’t have the money to cover the short term cost even if there are some long term gains.