1. Yes

2. I don’t think so. But the way way people describe the geography here is weird. Usually people say it’s the southern end.

3. It’s pretty sprawly, car is king, generally the threat of earthquakes and nimbyism has resulted in low density. I doubt ‘thousands’ though I’m not clear on your units.

4. Highly doubtful. The super-rich mostly live in the suburbs or exurbs of SJ, where it’s cooler (temperature wise) and less urban. Los Gatos, Mountain View, Palo Alto, Woodside, Menlo Park, Atherton, etc.

The electrical grids in general were fundamentally designed differently from country to country, including the voltage difference.

That took into account what was cost effective from the perspective of large scale deployment, and then individual elements are designed from (and are intertwined with) everything downstream from that. So even if two cities (one US and one UK) were/are nearly identical, the resulting grid is going to end up being laid out very differently.

The neighborhood in question was built in the late 1960s, underground has been the default for a few decades now but this neighborhood (along with many others through SJ) is just all old construction. There's no real justification for moving the power underground, even in rich neighborhoods most streets still have power via poles unless they're relatively new.

Electrical distribution plant generally follows the same code everywhere in the country. Also when SJ was first electrified it was a rural area.