Fittest only would survive is true for the languages too.
Nothing should be compulsory except the local language and English in Indian context of present times.
Let other languages slug it out in open for wider acceptance on their strengths. Only those which have street smartness, proven legacy of popularity, ease of learning, inclination for localisation and adaptability, vast vocabulary that a speaker never fumbles for a word would emerge victorious.
This is how powerful languages stayed concurrent for centuries. Kannada, Punjabi, Awadhi, Bhojpuri, Malayalam, Telugu, Urdu/Hindustani, Bangali or Tamil could be few examples of such power languages.
Those which could not become street languages of any geographical part in any era or which require state clutches to survive either left the battle field long ago or exist sparingly only for rituals and historical relevance or for love of pedantic exhibitionism.