Your narrative has some flaws. Startup events have been happening in India since past 10 years or so. Ever since Google won the war with Microsoft.
Flipkart was founded in 2007. Ola soon after. This H1B visa issue is more of past 2-3 year issue. Admittedly it will have some impact. But definitely not the narrative you paint.
Thanks for that link, I didn't know that. But in any case, my point is not that H1B can't be an issue for any case. But that Startups scene in India got a boost around 2005-2007, when many companies started, and it was nothing to do with the H1B visa issue. Some failed as well. Guruji the Indian search engine.
H1b visa issue is extreme for immigrants from India, and the rules over the last 15-20 years are to be blamed. Trump administration is only making it worse (for immigrants and crooked employers) by plugging every loop hole and interpreting the laws to the strictest extent.
The last 2-3 years it feels like its become extreme because:
1) Too much noise in media about new POTUS being hard on immigrants
2) A rising US economy means more demand for engineers. So there's more need of engineers, H1b or not. Hence more companies are getting effected by lack of access to such talent.
Flipkart was founded in 2007. Ola soon after. This H1B visa issue is more of past 2-3 year issue. Admittedly it will have some impact. But definitely not the narrative you paint.