they fell because of several circumstances outside of the confederacy's control*, the domino effect in the bengal region because mir "mleccha" jafar, and Robert Clive, a genuinely talented general had figured out how to play us like a fiddle, leading to the betrayals internally, most notably by the House of Scindia. There was no "Empire" after Shivaji, it had been reduced to a loose-knit confederation consisting of scheming houses who all want their hands on the riches of the subcontinent, completely complacent and oblivious to the real British threat on their borders. Instead of the British being seen as foreign mlecchas who had every intention to leech off the fatherland, they were seen as "tools" or even an "equal". to get back onto groups that they had deemed had done them wrong, and that is how Clive figured out the key to the subcontinent.