For software engineers, it absolutely matters. For the same reason it’s going to be a pretty weird discussion about Actor/Actress pay if you just ignore Hollywood.
The bubble means you currently get more in San Francisco, sure, but take the bubble away and you'd still expect the US average to be higher than the EU average as it is in other industries where there isn't a bubble.
For software engineers, it absolutely matters. For the same reason it’s going to be a pretty weird discussion about Actor/Actress pay if you just ignore Hollywood.