What was the reason for the defeat of the Marathas by the British?

Ideology. Or rather, lack thereof.

If early 19th Century Marathas had been preaching the same vehement style of Hindu Shahi that Shivaji and Sambhaji once had- forget the secular BS; both were so hardline on these matters that the average Liberal today would've had a heart attack merely talking with them- they'd have won handily.

See sections of the 80-point letter that'd once been sent to major Kings of the land…

Mark the vigour, mark the love for the gods, mark the derision for the Mleccha.

Even now some Hindus, even a few among the lamentably educated ones on Quora, have realised the basic truth that there's no population on Earth more fundamentally good-natured than the Hindu. Outside Liberal screeching, it's evident that no single Nation has been as accomodating, as self-effacing, and as eager to please the Other.

That's nonsense. Remember Machiavelli. Fear or Love, what is the right choice?

Hatred for the Other is the basis of Human Civilization. Quorans ask these days- “why does PewDiePie's fanclub hate us?”, “why do Whites persist in supporting jihadi states?”, “why do Jews seem to detest us even though we've done then no harm?”

Somewhere amidst all the politiking, all the luxury, and all the prosperity, the Marathas lost sight of the one great moving spirit of Humanity- Hatred for the Other.

We don't like to talk about such stuff; and indeed none are better at hiding their hatred of the other than a certain <<REDACTED>>. The Far East peoples, being less experienced in the Way of Empires, are therefore far more upfront with their Hate. But they're learning, and some of the consequent changes in their patterns of interaction can be seen already.

Technology can be bought. Losses can be replaced. Cities can be rebuilt. But the lack of a proper ideology will doom a people forever, as we can see with Hindus today.

Given the right ideology and true earnestness, Marathas would've not only crushed the Angrej but the latter would've themselves been praising Pune as well as defending any atrocities - or rather, improvements- the Marathas may have wroughg upon their populations. Instead of having TWs mock dead Hindus and praise their blood-stained Empire to the skies.

The only sin on Earth is losing. Everything else is justifiable. That's all.