> for some reason writing a for loop in SV is at least 3 times more valuable than writing it in London
I mean, yes, writing the same line of code at Google, Uber or OpenAI is more valuable than doing so at a British neobank.
You're correct in productivity being a nefarious beast to measure. But the examples given--extending the life of a high-GDP-per-capita person or doing identical work in dramatically different contexts--aren't making your point.