What brought the power of delhi to an end?

"Inherent weakness: First, the Turco-Afghan Empire was built on the power of the sword. It never rested on the foundation of the good-will of the ruled, without which on Empire can last long.Absence of strong rules: Secondly, the organization of the empire was inherently weak. The successors were weak and inefficient. If the reigning prince happened to be strong, it worked. But if the ruler proved a weakling, the whole structure gave away. Unfortunately after the death of Sultan Firoz on strong ruler arose and successive rule of weak kings hastened the process of decline.Unenlightened policy of the Govt.: Thirdly, the Turco-Afghans rules failed to evolve any broad and enlightened policy of government. They were mostly orthodox and intolerant in their views so that they failed to enlist the moral support of the Hindus who formed the bulk of the population.Mistakes of Muhammad-bin-Tughluq: Fourthly, the wild and visionary projects of Sultan Muhammad-bin-Tughluq plunged the country in hopeless chaos and confusion from the effects of which it was never destined to rise again.Absence of popular support: Fifthly, the Delhi Sultanate is based on military strength and not on popular support. As a result of this, when the military power weakened because of the weak Sultans, self- seeking provincial leaders and military generals revolted against the Sultanate. In the 14th century, many provincial leaders declared themselves free leading to the disintegration of Delhi Sultanate.Invasion of Tamer:  Finally, the invasion of Tamerlane, gave the final blow to the remnants of the Turco-Afghan Empire, so that fell to pieces almost immediately"

True,  spain conquered the incas and the aztecs for their gold and silver.