In Ancient India what was the key factor that made political power accessible to individuals, regardless of their birth status?

Ability to muster support and resources

As per the Shastras, only Kshatriyas were traditionally entitled to be kings. However, the origins of several significant ruling dynasties might not align with this norm. The social background of the Mauryas, who governed a vast empire, has been a subject of intense debate. While later Buddhist texts suggest that they were Kshatriyas, Brahmanical texts describe them as having a "low" origin. The Shungas and Kanvas, who succeeded the Mauryas, were Brahmanas. In reality, political power was open to anyone capable of garnering support and resources, and it seldom relied solely on being born as a Kshatriya.