There have been many self proclaimed god men and mystics in India. Most claimed to have supernatural powers. I myself am an astrologer who studied Jyotisha. Why couldn’t astrologers predict the fall of India? Many historical figures even claimed they performed penance before they went to war. But the Indian subcontinent still got invaded and conquered despite all of them god men with supernatural powers. Was it because of the unfavourable planetary forces that was unavoidable or karma, the country as a whole had to pay?
I have a different opinion on this issue, I have always felt that it's the greed or ambitious nature of few of our own people that have led to the foreign invasions or in other words inner information leaked by trusted close aides to the enemies led to our downfall. Even in modern day we can find few people who even though call themselves as Indians but in exchange of money they are working for others, be it in the name of religion or something else.
Citing few examples below:
KING AMBHI KUMAR:
When the mighty Alexander made his way to India, he was welcomed with open arms by the King of Taxila, Ambhi, who offered his submission just to see the ruin of his arch rivals- the kingdoms of Paurava and Abhisara.
RAJA MANN SINGH
In return for aiding the capture of Tatya Tope, the Raja was promised the return of his lost jagir (a feudal land grant) at Gwalior.
He was among the weak rulers and the most treacherous of all Indian traitors who chose the wrong side in the Rebellion of 1857.
RAJA JAYACHANDRA RATHOD:
Jaichand joined hands with Ghori to ensure Chauhan’s defeat.
Mir Jafar made a deal with the British East India Company: Jafar and his cohorts agreed to hand over the Bengali army at the Battle of Plassey in exchange for control of the new puppet state.
DAULAT KHAN LODHI
Daulat Khan Lodi (wasn't a native of India though) was the governor of Lahore during the reign of Ibrahim Lodi, the last ruler of the Lodi dynasty. Due to disaffection with Ibrahim, Daulat invited Babur to invade the kingdom, this led to The First Battle of Panipat (A.D. 1526)
India lost to foreign invaders because Indian rulers did not update their weapons and military tactics. Indian armies kept relying on elephants which proved unreliable against Alexander in 330 BCE. They learnt nothing from this defeat. They kept using elephants even in 1050 ce (1300 years after Alexander) against Mahmud of Gazny who used fast moving cavalry to devastating effect. Moreover Hindu rulers did not attack Mahmud in his homeland of Afghanistan but were always at the receiving end of his attacks.
This is not just true of Hindu rulers but also of Muslim rulers. Ibrahim Lody's army lost to Babar because Indian armies have never seen a cannon and didn't know how to handle mass cannon fire. This is not the end of the story. Mughals also did not update their weapons. Mughal military technology also did not keep pace with European technology. This caused a severe military imbalance by 1740s. A French army of 200 men routed a 10,000 man army of Nawab of Arcot in 1746. Why did the Nawab lose? His army lost because his cannons fired 1 shell every 3 minutes while the French cannons fired 20 shells every minute, i.e., Mughal cannon technology was 150 years behind European technology. Thus when the cavalry of the Nawab charged the French they were subject to 60 shells per 3 minutes when they were expecting only 1 shell in the time period. Naturally Nawab's cavalry fled. Europeans noticed this performance and after 1746 began to systematically take over India. In fact even during Auranzeb's time Mughal armies used to have English and French gunners.
The Marathas rose to prominence from about 1703 because they copied Mughal tactics and in fact improved on it. They used fast moving cavalry to harass the Mughals. Baji Rao's cavalry managed to invade Delhi by 1738. Maratha Generals also had European gunners in their armies. This proved a fatal weakness when the Marathas faced the British. In some of these battles against the British the European gunners in the Maratha armies were no show against the British.
This refusal to update military technology and tactics continued even after independence from the British. It was clear as early as 1957 that Chinese were building up their military strength in Tibet. Did Nehru take any meaningful action? No, he did not take any action until late 1961 when it was too late. I must add here that this blinkered attitude is not the monopoly of Hindus. In 1940 when the Nazi Army made a massed tank assault through the Ardennes, the French Generals were advised to cut the trees of the forest to slow down the Nazi blitzkrieg. Did they listen? No they did not take that advice because the French Army General staff were confident that the superb French cavalry with their long lances and rifles could stop the Nazi assault. This refusal was in spite of the lessons learnt in World War I where the cavalry charge failed against massed machine gun and artillery fire. So what happened to the French cavalry charging the Nazi tanks. The french cavalry was found to furiously gallop back into France as soon as they came under withering machine gun fire from the Nazi tanks.
Thus it is clear that in the 1000 - 2000 ce period Indian rulers, Hindus, Muslims and secular Nehru, have all neglected their military and not kept pace with the advances in military technology and tactics. Naturally this led to defeats and slavery. The question raised here is if this apathy in military affairs is due to Hindu teaching. I would argue that it is not due to Hindu teaching. Recall this famous Gita shloka:
O Arjuna! Whence has this loathsome stupidity come upon you in this crisis? It (this attitude) is unworthy of a noble personage; it is bar to heaven and a cause of much disrepute.
Lord Krishna did not ask Arjuna to meditate or go to an astrologer. He asked Arjuna to fight. It is thus an obligation for Hindus to fight and obviously updating military technology and tactics is a must. Hindus did not follow the Hindu teachings and hence they were defeated in that 1000 year period.