Definition of success is extremely difficult to be given here.
I will give you a small example. Literacy is a big problem in India. Unfortunately since you can't read or write, your access to information is limited. This puts things like news papers and magazines outside your reach. Access to any kind of information will be weak(Access to information is the most thing for a person in the modern world)- You won't be able to make well informed decisions about anything, your knowledge of current affairs will be weak. Ultimately such a mass of people won't be able to make it big.
This is why basic education should be compulsory. Also these days knowledge of the English language is extremely important to do any work with people of other nations. English is not our native language or mother tongue. So we learn it only in schools.