California's a pretty damn big state. The total area of those five states is only ~70% more than California, and that's counting all the central and northern bits of Michigan that definitely aren't part of this, and eastern PA.

California is a big, but generally unpopulated state.

Approaching 40 million, that population is divided, generally, as: half in the Los Angeles - San Diego region, half the remainder in the San Francisco - San Jose region, half the remainder (5 million) between Sacramento and Stockton, and the remaining 5 million throughout the rest of the state, mostly still within the southern Central Valley (particularly Bakersfield).

See: counties by population, showing 23 counties of fewer than 100k population. Over half the state's population is in 5-6 counties: Los Angeles, San Diego, Orange, Riverside, San Bernardino, and Santa Clara.

https://www.california-demographics.com/counties_by_populati...

I'd say the equivalent to the SF Bay Area surrounding area would be Seattle, Los Angeles, Portland, and San Diego. One could definitely argue those areas are even more vibrant than the combination of Cleveland, Pittsburgh, Cincinnati Chicago, etc.

I dunno... the polygon the author drew is only about half the area of California.

On the other hand it's kinda cheating to put the major cities at the corners.