India has a population density of 1264 people per square mile, and the US has 96. With the same density, that would give the US 4.6 billion people. With the current population, you would need 17.5 million people in the streets to match this, but to build that kind of momentum is difficult when your largest city has 8.5 million, and the next, at 3.9 million, is over 2000 miles away.