The answer is probably a combination of things. We need to be able to build more houses / duplexes / apartment buildings / etc. That's a fact. There could be ways to help people build their own house (up to code) and cut out the middleman.

If people could easily build their own, do you know how fast property values would drop? Homes in the middle of nowhere should cost nothing.

My answer, cap the number of single-family rental homes in a given jurisdiction. Give 5-year chits that authorize a property owner to rent the property, then every 5 years have some sort of event that allows someone else to take the chit. That way you don't have 80% of the single-family homes being bought up for rentals and it doesn't bar the market from having new people enter.

As for the event, my preference is for a landleech Thunderdome. Two blood suckers enter, one leaves, and they are allowed to profit off someone else's hard work. Corporations are allowed to participate by champion proxy, but the champion must be a C-level executive and they must participate in every match for every property they rent.

Apartments and multi-family homes (duplex, triplex, etc.) can be rentals as far as I am concerned because there is room for it in society, but housing needs to be put in the constitution as a right (as does food) and rent has to be more regulated.

It is honestly not. Property ownership is currently the primary method for being able to collateralize small business loans. Without the general populace having access to that, that initial step for starting a new business or pursuing a venture before it is viable for investment becomes VERY difficult to achieve. Especially if it is something that requires a lot of involvement or time to get moving. Once you take out the ability to make a startup or small business, you are left with an ever-dwindling pool of options and end up in a persistent state of monopoly it oligopoly for most goods and services, which in turn leads to an utter stagnation of economic conveyance and growth.

Another way it stagnates economic growth is in the increased expense associated with housing. The actual economy, not the BS we are told is the economy, grows when money moves. Individuals and companies buying goods and services from each other. That only happens with disposable income. If everyone is paying 2x what they would in rent that they would in ownership, that comes out of their disposable income. This leads to less luxury (in an economic sense) purchasing and, in many cases, restricted necessity purchasing. So less money is available to move, which causes the economy to shrink.