But you wonder how the colonialists managed to colonise in the first place...
I mean if the culture is rich and beautiful, it's still useless if it crumbles at the sight of the first merchant ship from thousands of kms away.
Point being, the indian intellectual culture is enjoyable but it did not focus enough on what could have made people able to stay free, and stealing part of the invaders ideas to reinforce the local ability is not bad, it's the only way to resist the next wave.
To simplify grossly: less worship, less obedience, less birth hierarchy, more political alliance with neighbours (so that you're not surrounded by sharks when you're in trouble), more national awareness (opposed to tribal), more ability to quickly iterate even if elders disagree (so that you're the one with a big innovative merchant navy) . It feels that's what made some countries rise super fast and start colonising while others went rotten and self destructed.
My country, France, is a few kms away from England and they stopped being able to colonize us long before India, so what was missing in India, so expensive to invade ? (ofc, France also horribly colonized countries and we should have had the maturity not to, but guess what we told our own protectorates when we came: look at England colonizing your neighbour, let us "protect" you so you can compete...)