So basically, landlords collude with local governments all over US (I don't know how it is in other countries) to prevent the real estate rents/prices going down by making politicians restrict building more housing wider, and building more housing higher.

The economic impact on the economy is staggering. GDP reduced by $1.6 trillion a year. That's $1.6 trillion in lost economic activity, money people could have used to build up their lives, happiness, hope for the future, and one of the reasons millenials struggle to launch their lives.

Americans now spend the highest percentage ever of their income on housing. This is money that could have been available in the economy for general consumption.

Links to the academic study:

http://faculty.chicagobooth.edu/chang-tai.hsieh/research/growth.pdf

https://www.nber.org/papers/w21154

Press coverage:

http://www.citylab.com/housing/2015/05/the-urban-housing-crunch-costs-the-us-economy-about-16-trillion-a-year/393515/

http://laborcenter.berkeley.edu/the-high-public-cost-of-low-wages/

http://sfist.com/2015/05/13/study_ny_and_sf_rents_are_dragging.php

Another press article highlighting the issue:

http://europe.newsweek.com/affordable-housing-rent-burden-census-income-inequality-333350?rm=eu

What you can do:

Anything. Start a website or a movement demanding high level government action on the issue. Tell your friends. Silicon Valley tech industry or a wealthy individual could bring awareness to this issue in a major way.

The desired end result is a congress or presidential level action on this issue that could boost GDP immensely, improve the quality of lives of millions and give the American dream some real wings again.