There was a time when this wasn't. The thing is that it _is_ now, especially for people in the upper-middle class and above, who can and do live a WAY better life in Mumbai, however much you try to deny it. There are people who've told me they wouldn't bother living in the Bay Area had it not been for the money, weather and inertia. I am now also seeing a lot of NRIs who are grasping at straws to justify their living in California, something which they didn't even need to bother with 20 years ago.
> The crosswalks in SF and San Jose exist
I find it funny that you have to reach all the way to crosswalks to make a point. The places where you cross the road? What makes you think they don't exist in Mumbai? What about so many places in the US where you cannot even walk on the road if you don't have a car?
You can try and convince people who haven't been to Mumbai at all, or don't live there regularly. People who are well-off, have lived in both places, and especially those who might _now_ consider starting a life in the States: you'll pretty much need to provide a utopia or an extremely high-paying job to convince them to move there. Mumbai is hell, there is no denying that, and even locals will not fight you on it; I personally would not try to convince a non-local to consider Mumbai as a place to live. The problem is that the Bay Area is not the heaven, perceived or real, it used to be any more.