Present estimates put it between 50 - 150 years. Yes, I kid you not. The path to GC for Indians, might as well be closed shut for all intents and purposes.
https://www.am22tech.com/eb2-india-predictions/
https://medium.com/@happy_sushi_roll/the-endless-wait-for-a-...
* It's better than the alternative, and it can be made to work, since once I140 is approved you can renew H1 indefinitely (unless sth goes wrong, like right now, but that's a risk that doesn't look so big initially when all is still well).
* The wait only became this bad around 2008 or so. At the time, nobody knew there wouldn't be a realistic chance to get to gc. A lot of people have been in the system since that time.
* It doesn't always start with wanting to move to the US permanently. You go to a US college, or move for a job in the US (maybe the company you've already been part of offered it, maybe not), thinking it'd temporary. Then you build a life, make friendships, and realize you want to stay.
* Or maybe your parents moved when you are a kid and the US is all you know. But when you turn 18, it's F1/OPT/H1 or go to a foreign country (that you happen to be a citizen of, but have no real relationship with).
Above are all real examples I personally know.
Also, while for non-Indian immigrants it is at least possible to get a gc eventually, this is also by no means certain. Very stressful as well.
The green card process on the other hand just takes however many weeks or months it takes to process the paperwork. But there is a per-country limit per year. So if a vast number of people from your country are tying to immigrate you can end up in a really long line.
Citizenship has the requirement of being a permanent resident for a fixed number of years before you can apply.
At the same time there isn't any practical way of immigrating to the US other than being very rich, very specialized (and Outstanding) or a family member of a US citizen.
What is more fair? A guy from Island waiting 20 years because he is stuck behind 1 billion Indians? Or Indians waiting longer because more of their nationals are applying? Honestly, I don't know, but I know the 7% rule is justified. The idea is to avoid massive inbound diaspora that would be very hard for the country to absorbed culturally.
Also, EB1/2/3 wasn't supposed to do diversity, that's what the diversity lottery is for.
Also, the limit could've been applied to visas instead of greencards. I don't see how keeping people in limbo inside the US for decades/lifetimes is reasonable. If they are here de facto permanently anyway, they should get a path to citizenship. A two-class society is wrong.