This has no effect on someone's ability.
- went to one of the top schools in the world, such as Stanford, MIT, Harvard, etc
Those are not "top schools in the world". The only advantage they provide are great contacts and opportunities thans to those contacts. In terms of knowledge, many schools around the world (including many in the former Eastern bloc) provide excellent education.
> - has an extensive personal portfolio of software projects on which they contributed
Again, this has nothing to do with being in SV. Many bast-known open-source projects were started outside US (I'll leave it to someone else to list them, but I'm sure you can think of a few off the top of your head).
ADDENDUM - An example of your bullet points working just as badly more recently than 30 years ago:
Cevat Yerli when he started Crytek
- has experience working in the early stages of a venture-backed startup
- went to one of the top schools in the world, such as Stanford, MIT, Harvard, etc
- has an extensive personal portfolio of software projects on which they contributed
My point is that Silicon Valley "works" because it has lots of people that meet 2 or 3 of these bullet points. There is no place in the world that really comes close.
Nobody is objecting that you can surely hire people cheaper in other countries, but for small companies the cheapest labor source is almost never the winner. It's far more important to have the very best engineers.