As of 2013, India had a GDP per capita of $5,200, as measured in 2005 dollars. For comparison, the US had a GDP per capita (again, measured in 2005 dollars) of $5,200 in 1881.
For Haiti, the comparison is even more brutal. Its 2013 GDP per capita was $1,650. In 1800, one of the earliest years for which we have data, the US's was $2,100.
There are obviously limitations to these kinds of comparisons. Some Haitians have access to technology poor Americans in 1800 could only dream of, and our GDP data gets less reliable the farther back you go.
But the comparison nonetheless illuminates just how much poorer developing countries are. This visualization, made by Vox's Kavya Sukumar using data from Gapminder, lets you select any year in American history and see which countries were richer in 2013 than the US was then, which were poorer, and which were about equal (within 10 percent):
The good news is that global inequality has fallen substantially in recent years due to economic growth in developing countries, particularly China and India. Many analysts think that eliminating extreme poverty by 2030 is, while not inevitable, certainly possible. But even if we get to a point where no one is living on less than $2 a day — a huge improvement, given that about a billion people live below that poverty line now — most humans will still live in what Americans would consider deep poverty. After all, $2 a day is still just $730 a year; it'll be a long time before everyone on Earth is able to live on $10,000 a year or more, which is about where most rich countries draw the poverty line.
For more on global inequality, be sure to read economist Christoph Lakner and Branko Milanovic's recent paper "Global Income Distribution: From the Fall of the Berlin Wall to the Great Recession." Also check out Milanovic's paper "Global Inequality of Opportunity: How Much of Our Income Is Determined by Where We Live?" (The answer to the titular question? "Most of it.")