I learned that in the future, stacking mobile homes in impracticle mobile home racks is apparently more cost effective than replacing mobile home parks with tenement housing.
Probably inspired by this:
https://en.wikipedia.org/wiki/Kowloon_Walled_City
Ha, I was just thinking of that. Kowloon Walled City was the most densely populated place on the planet at the time. And it was effectively lawless, being entirely surrounded by British Hong Kong, which was in turn an enclave of China. Neither government was interested in sending police there.
What's sad is that modern day living conditions in Hong Kong are even worse, with many people living in "apartments" the size of American parking spaces. It's not even a problem of lack of land, as many believe. The government leases land to the highest bidder, and few of those bidders are interested in building residential housing.