Why do people from India not wear western clothes when they leave India for a western country?

I have some Indian friends who are completely American (I'm American). Seems like the older Indians like to preserve their culture, however, assimilation is inevitable over time.

it's because of pride, honor, heritage, something they want to bring to America to show us who they are and how they live. Visitors are one thing but when you move to another country and stay the same old way and don't change then you're considered a person who doesn't want to "meld" and take responsibility and be one of us, a citizen, someone proud of our country, so they then just don't fit in and it was their choice to make and they did.

Usually the second generation American still knows the language and traditions and honors them and their parents and hangs on as long as they can to the customs and such of the old country. but those born third generation American are usually Americanized. they've learned that if they're going to fight the system they minds well go back home.

"most people like to be like the country they move to"

Really? I don't really see this among ex-pat Americans who go to live in the middle east or east asia. They still wear the same clothes they did back in the states. But that's different, right?