SV is ground zero and probably will be for some time, but the forces of present immigration climate are unlike it has ever been in the past, and I wouldn't be surprised if it topples SV's position as the innovation hub in the near future. In the past, immigration was a minor barrier comparable to other barriers founders and innovators face regularly, but one that needed to be overcome. Today, especially with the freedom of the global internet infrastructure together nationalist political climates, immigration is starting to look like a less and less savory distraction that doesn't even justify the effort needed to overcome it.

The immigration situation for skilled/educated workers, has to my knowledge, always been extremely bad in the US. Right now, it's gotten worse to another level, but it's not like it was anywhere close to good before. There is no founder visa. A few rare people (including you) have managed to get the O-1 visa; but that's usually an extraordinary difficult endeavor. Even getting a new H-1B is incredibly hard, with your chance of winning in the lottery less than 40%, and there being a significantly long (~7 months) before you can even start working. Moreover, you're prohibited on having majority control over your company on an H-1B, and need to ensure there's a board that can fire you. So there's that.

Then there's getting an EB-1 approved ... I don't how you managed to get it, but kudos to you on that. From what I've read, it's incredibly difficult, and usually an order of magnitude more difficult than getting an O-1. Immigration guides often say you need win the Nobel Prize in order to qualify for it. But I've also heard luck plays a huge factor -- in terms of who your adjudicating officer is. Anyways, there's very little info out there (on the interwebs) that talks about how to succeed with an O-1 or EB-1 application. (It would be great if you could write about it.)

Getting an O-1 and EB-1, rather than being some extraordinary feat, is more of an extraordinary distraction, and yes luck factors into it a lot.

My understanding is if you tried to immigrate 8+ years ago, it was relatively certain and less of a distraction, even if it still took ~12 months to be done. It has gotten gradually harder every year, until it went up asymptotically in 2016 (I finished applying for my EB-1 in 2015).

Unfortunately IANAL + immigration landscape is evolving constantly, + the complexities and options of immigration vary wildly with the differences in personal circumstances (from passport to education and work history), so anything I write will be quickly obsolete, and most people would find it either too generalized, or not applicable to them.

Feel free to DM me, I'm happy to share some advice with anyone who thinks immigrating will be important for their career.

imho from talking to many first time founders there is already a decrease in demand/aspiration to move to the states

part political climate, part living cost in sf/bay, part network becoming more global etc

Absolutely. No offence, but we wouldn't touch the states with a bargepole for all the reasons you mentioned.