You're describing two different problems. Housing supply in the Bay Area and New York -- the areas I'm assuming you're talking about, because most other metropolitan cities are building to keep up with supply just fine -- is incredibly low. In addition, in the Bay Area especially, the incredibly high salaries in combination with that supply is causing skyrocketing prices.

Be aware that Silicon Valley is an extreme global outlier in real estate prices.

Not really, there's cities all over the world with conditions that lead to crazy high real estate/housing costs. Most every metropolis ends up with a similar situation. Slightly different settings that all sum up to "high demand low supplies". NYC, London, Vancouver, Hong Kong, Tokyo, ...

SF is an outlier compared to London. From expatistan.com:

Monthly rent for 85 m2 (900 Sqft) furnished accommodation in NORMAL area:

SF: $3,663 (£2,789) London: £1,766 Difference: 58%

Worth noting that the difference there is exaggerated somewhat by the unusually low value of the pound at the moment.

Worth noting that tech workers in London make about 1/2 to 1/3 of what they do in the Bay.

It might be worth noting in another context, but tech worker salaries don't determine London rents.

The unusualness of the pound is about 10%, +/- the usual variations, isn’t it?

Depends on what period you're considering:

https://www.macrotrends.net/2549/pound-dollar-exchange-rate-...

If you take 1.6 USD = 1GBP as typical of recent times, then it's more like 20%.

Is this true when you are comparing similar conditions? Something along the lines of: Large cities with significant multiculturalism, high tech jobs, significant culture (arts, media, entertainment, museums, etc.), public transportation, and openness to various ways of life

Yes. Try moving to Minneapolis, which has plenty of everything you ask for and housing prices are not out of control. If you don't need a large city, Des Moines does well too on the rest of your qualifications.

Not Compared to London though - London does have a much better transport system so living 60-70 miles away and commuting isn't as bad as it would be in SV.