why didn't ancient persia ever conquer india?

I really feel offended by these type of comments. People who make these comments should gather their facts more carefully. Baluchistan was never really seriously part of the Persian sphere of influence. There were three Persian empires which exerted influece in this region. The eastern part of the Sassanid empire was hotly contested and it could never be called a real part of the Persian empire. The Saffarid empire controlled western Pakistan for a very a short while and it was not actually ruled by a proper dynasty but rather just a warlord dynasty rather like the Lodhi one. And the Saffavid dynasty ruled only a tiny part of Balochistan. The change of language from a Indo-Aryan one to a Iranian one is very recent considering the antiquity of this region. Before the 12th century the population of Baluchistan was speaking Indo-Aryan Prakrit and only with the arrival of the Westenr Iranian Baloch's did the language changed to an Iranian one. But the history of Balochistan goes very far back in time with the Mehrgarh culture from 10,000 years ago and hence this Iranianization of Baluchistan is very recent. Similarly NWFP historically known as Ganshara the Pakhtuns originally a mountain tribe as indentified by Herodotus moved to south east into NWFP and assimilated a population which spoke the Pothohari Indo-Aryan tongue of hindko and which can still be found mainly concentrated in the cities and comprise 30% of that province's population. And considering the history of this region that too is very recent. Pannini lived in the Peshawar valley and he spoke Sanskrit and the vernacualr language of the population was also a dialect of Sanskrit as his work was on the difference between Vedic Sanskrit and spoken Sanskrit of his times .

So i really don't get what you mean by saying that Balucistan and N.W.F.P have historically been always a part of Persia than ruled by the dynasties from what is now Pakistan. Please back up your claim with historical facts.