You don't have an iota of understanding about the language dynamics that led to the creation of India as it is today. Also language is culture, culture is identity. So people use their native languages with pride in India. Also Hindi is not the language educated people communicate in India - It is English. In fact the BIMARU states which use Hindi are the least developed among Indian regions with lowest literacy. South India in general developed primarily as we adopted English as our 2nd language long back which opened us to opportunities around the world and also cared to nurture our mother tongues. It is proven beyond doubt that mother tongue education is vital to the intellectual and social development of a child. Languages are a biological part of you and not a device that may be discarded at will (learn a bit about modern linguistics). The idea of single language for India has been rejected by its parliament and people (by the way, it is nothing but fasicsm - as an adjunct I can argue that the whole humanity must adopt a single language - does it make any sense??). English is the communication link of India, and that is the best outcome. So if BIMARU states give some importance to English, they also have a chance to develop.