I think having the option of really small low quality accommodation in big cities is good, but let’s not pretend Tokyo/Seoul/HK aren’t just as expensive per sqft as NYC/SF/LA.

Checking online, the average price of an apartment in Santa Monica is $55 per square meter. SF is about $53. NYC is $65. Tokyo is about $27, Seoul is $23

So no, Tokyo and Seoul are not "just as expensive". HK is at $52 though so that was a bad choice on my part.

They aren't more expensive. But besides real-estate, they are practical. You don't need a car; and an affordable 24H 7/11 is always downstairs. Also you can stay at the cheapest neighborhood and don't get stabbed; can't guarantee the same in NYC/LA/SF.

They aren’t as expensive per square foot. Sure, Tokyo apartments tend to be smaller, but they aren’t that much smaller. It’s more an efficient use of space than anything.

Hong Kong also isn’t comparable to Tokyo, and is much more expensive.

I can’t comment on Seoul.