If you want to write software to make money you have to provide something people want.

Figuring out what people want requires doing market research in the US.

Assuming that a software company in india can do that kind of research 100% remotely (without people here in the US); they'd have to raise funds to start their own company. India's Venture Community is not quite as well developed as the US. And the banking/financing system is not as well developed, so obtaining loans from "1st Bank of Bangalore" might be an issue.

Now, assuming that they have an idea, they have the money to start the company, and they've got the product... they STILL need to come to the US and market and sell that product to the firms in the US.

So the strange thing is it still requires workers in the US, and some level of US production. Consider, while the Japanese back in the 80s produced autos and imported them--- after a while, they needed to move sales, marketing, and manufacturing to the US to ensure that what they were making addressed US needs.