The government has already introduced measures such as the mid-day meal to encourage children from economically backward homes to attend school. (I suggest you do some research on other measures that the government has introduced)
Children who fail classes lose interest in studying and are more likely to drop out. Parents whose children fail feel discouraged, and if they are not well-off, feel that it is a waste for them to pay for education. Already, schools cannot fail children till the 9th Std. This means that there will be less school dropouts in the 6-14 age group, which is what RTE targets.
When we are forced to cater to ALL children, not just the ones that fit into the cookie-cutter mould, we will have to rethink many of our current, outdated systems and constructs of education.
RTE also requires 25% of seats, even in private schools, be reserved for economically backward students who will not pay full school fees, but will be subsidized by the government at a rate they consider acceptable. This will lead to fewer schools being run for a purely profit motive. Schools will also have to rethink their approach to teaching when they have to deal with a mixed group.
This 25% cannot be put into a separate division, so even children from wealthy families will be mixing with kids from poor families. As a direct result of this, they will grow up to be more broad-minded.
In order to ensure that children are learning what they need to, in spite of not failing classes, new methods of assessment like CCE are being introduced in both the Central and in many State Boards.