You're asking the wrong question. Individual Indians, Bangladeshis, and Pakistanis can easily "become part of" a western democracy. The real question is how these immigrants can maintain and perpetuate an egalitarian western democracy. At the scale of immigration Canada and the US is experiencing, you can’t take for granted that the immigrants will simply maintain the kind of society that’s currently in place. Democracy doesn't arise from putting certain rules and constitutional structures down on paper. Instead, it’s the expression of the civic culture of a people.

That culture, in turn, isn’t about superficial stuff like food and language. Who wouldn’t think Indian food is a good thing? But what’s important to maintaining and perpetuating a democracy is deep culture. How do people in a culture view relations between people in society? On the sub-continent, we have an intensely hierarchical view of society, where we place great importance on people’s breeding (coming from a “good family”). Family ties and personal relationships, moreover, are much more important than abstract rules. People are much more willing to cover things up or bend rules to protect personal relationships than in the west, making the sub-continent a breeding ground for corruption. Asians, in general, come from societies that had millennia of large-scale imperial government. So the view of the relationship between the government and the individual is very different.

I'll give you a concrete example of the distinction. My family easily assimilated into the Virginia town where I grew up. That only means we can function—very successfully—within an environment where the norms are imposed by some other culture. We couldn’t recreate that environment. My mom can function in a society where norms of egalitarianism are imposed by a dominant culture. But that’s just not how she sees the world. She looks down on "the common people" and think that society should be governed top-down by people of good breeding and education. Because that’s a foundational assumption in our culture. And if suddenly 20% of the population were like my mom, the environment would become less egalitarian.

In fact, that's exactly what happened to my town. We went from being a quintessentially American middle class town to having a large number of affluent, educated Asians move in. And they completely changed the environment.