I'm not assuming anything, I'm making an assertion--an assertion that could be right or wrong. In particular I am not assuming/asserting that India or S.A. would not have made progress.

I am saying that the effects of colonial rule are so unstable and so varied that it can be difficult to the point of meaninglessness to say a country would be "better" or "worse" without it.

The Bengal Renaissance is a documented movement, founded and driven by people exposed to Western thought. That doesn't mean the movement wasn't theirs, that they weren't the ones producing "intellectual" information. But they were in a different place because of colonialism than they would have been without, one where Indians went to school in Britain and where people were writing letters to each other across the ocean.