Shalwar kameez is easier to wear and maintain, hence younger generation choose this over sari. My wife wears sari for like once an year. Daily wear is slowly shifting to jeans and top.Of course it is more diverse but it is slowly being homogenized and those vast regions of India have now shifted in the way described in my infographic. Kerala, Assam, Tamil Nadu, West Bengal or even Delhi look more "Pakistani" then they did 40 years ago. Today majority of women from reports I have seen wear shalwar kameez and often have a scarf draped around their shoulders. The ubiquitous Indian Sari is now a rare sight even in south or east India.
And Pakistan was always more homogenous given our compact [relatively] geography and long, shared history.
@masterchief_mirza Whilst this process of Islamic culturalization is taking place the strange thing is there has been rise of Hindudtwas who claim to be out to clean India of the foreign Islamic culture and influence.