The strict land use laws were enacted because of high rents and high land prices, not the reverse as you imply. As an investor, when I see a place that has sharply increasing rents such as a town like San Francisco my goal would be to build as many units as possible to maximize my rent and sales revenue. In towns/cities without strong land-use laws (and there aren't too many), I can buy up cheap real estate, tear down the exisitng structures, and build as high as it makes sense to maximize rents and land value. Most places where this is possible are in relatively dense cities where population income is higher than the norm such as Singapore, London, Paris, and Rio, along with SF and Manhattan in the US.

Without strict and-use laws, it would be easy to buy up the two - four story buildings along Oak and Fell (and along Lincoln and outer Stanyan), tear down the existing buildings, and replace them with 20-50 story high-rises. If San Francisco would give me that power, I'd become one of the richest people in the world.

Many valid points against San Francisco's current planning process have been stated here before:

1) The huge economic wealth created from new construction accrues to the developer, the banks financing the deal, the lawyers, and the PR firms, while the exisiting residents are stuck with most of the external costs of the project, including more congestion, added stresses to existing public services such as parks, police and transit, the loss of light, and a loss of place.

2) The residential units that get built do not meet the current needs of the exisiting residents since a developer's goal is to maximize rents and land value by renting and selling the units to the wealthiest population groups, such as foreigners looking for a place to park a few of their millions, or US millionaires looking to buy another 2nd or 4th home in a "cool city" to hang out for a month or two each year, or the units are marketed to the newly minted tech millionaires created on a weekly basis at companies often not even located in the city.

All one needs to know about the SF Planning Dept, mayor, and BOS is that none of them can tell us the purchaser profiles of the 10,000 units built during the past 12 years, such as where the purchasers lived two and five years prior to their purchase, what was the source of their downpayment, and the percentage of full-time residents living in the purchased units verses whether the units are being rented out as an investment.

Developers and land speculators in the US have it esay. In many places around the world that face housing shortages and sharply increasing rents there are severe restrictions on who can puchase a city's limited housing stock, often preventing foreigners, part-time residents, investors, and a whole host of other exploitive economic players from the market so that the exisitng community does not face the severe dislocation that happens when a city is under siege by outside money. Fortunately for developers, speculators, and real estate investors, San Francisco is a solidly Democratic Party city, and the Democrats are closely tied into big-city landlords, developers, real estate speculators, and big ticket transpo across the country.