After Independence, why was there a reluctance to divide the country on linguistic lines?

In 1920s, the Congress had promised to divide the country into states along linguistic lines. This promise was made for administrative convenience, and had massive public backing.

The Independence of India had come at a very heavy cost. The country had been divided into Indian and Pakistan along communal lines, which led to massive displacement of humanity and bloodied riots fuelled by divisionary forces. Consequently, any further criteria of division between people were seen as a threat to the safety of the nation. Hence the government was wavering from its earlier stance of drawing out states along linguistic lines.