Investing on education is good for the future of a country but when a country keep investing on education and start producing more graduates year by year but they failed to make the enough employment opportunities for them will make the economy into mess again. Graduates will start working for less pay and the remaining will move to other countries for better salary and pay taxes to those countries but at the end one who produced the person will be benefiting nothing from it.
If a underdeveloped county put a larger budget for the education, it may not show the results in the initial years but later once the education population is ready to serve the country, very likely the country will prosper and enter in the list of developed countries. Investing in education is good for the long term development of the nation.
But as he said before, inbalanced allocation of budget may also be a factor even though investing in education is good for the future of the economy. It might make your country educated, but having graduates without jobs waiting for them is common in different countries that strives the same concept. This can cause to many unemployment due to the scarcity of the availability of the job for their courses.