Modular apartment buildings also exist and can be thrown together quickly and affordably.
Not to be rude, but the problem is likely going to take a bit more to solve than throwing shipping containers at it..
$1000 a month for a brand new 740 square foot apartment in the middle of San Francisco. Plus with modern finishes that are frankly much nicer than anything you'll find in the low-end SF rental market. I'd imagine quite a lot of people would sign up.
This is mostly from an NYT article, so perhaps it's just one school if thought among many, but I found it convincing on the merits. https://www.nytimes.com/2019/08/14/opinion/shipping-containe...
I'm in a high-demand city in Canada. The house I'm in right now is worth about $70k. The land it sits on is worth $900k. Shipping containers aren't going to help with that.
Don't know where you live, but I doubt it's more expensive land than San Francisco, where the average acre of land costs $3.2 million[1]. Taking that acre of land, save half the area for green-space and courtyard. Use half the footprint for shipping containers. Stack the containers 8 high.
You now have 242 double-pod units. The amortized land cost per unit is $13,000. Assuming a generous rental yield of 12%, the land cost only adds $130 a month to the rent. That's hardly anything for a 720 square foot apartment.
The lesson is that even San Francisco land costs are no match for the power of high-rise high-density housing.
[1] https://www.6sqft.com/study-shows-huge-disparity-in-u-s-urba...
If cheap, abundant, shipping containers pull 25% of the demand out of the low-end multi-family segment, that's a 50% drop in prices. Low-end housing is a substitute good with mid-end housing for at least some of the demand.
The prime example are people who live with roommates in mid-end housing, who with cheap enough low-end prices, would get their own place. A 50% price shock to low-end multi-family at the very least would pull 10% of the demand out of the mid-end. That would lead to a 20% drop in mid-end multi-family prices.
Just the same there's at least some substitutability between mid-end multi-family and mid-to-high-end single family. A prime example are empty-nesters looking to downsize. With a 20% price shock to multi-family, that would suck at least 5% of the demand out of the single-family segment. That's a minimum of a 10% price reduction.
Hence a positive supply shock in the form of cheap, abundant shipping container homes would reduce the price of mid-high-end single family homes by at least 10%. This is all micro-econ 101.
95% of the work can be done in overseas factories and is subject to the same globally competitive downward price pressure as every other manufactured good. Build them in Shenzen at a wholesale cost of $30,000 per pod, ship them to San Franciso for $2000, stack and install them at a cost of $8000. At 320 square feet, that's $120 per square foot. The same cost as new homes in rural Texas.
All the California legislature needs to do is pass a law zoning everywhere in the state for multi-story shipping container apartments. Then watch prices plummet. Even for single family regular construction homes, because the shipping container apartments will suck so much demand out of the market.