When I was a kid in Minneapolis, my parents bought a house and six years later sold it for twice what they paid for it. It was possible because the house was a dump when they bought it, and my mom redid the entire interior (floors, walls, ceilings) by herself, learning on the way (she then did it commercially for about 15 years). That kind of "flipping" is what should be allowed.

Where I live in Vienna, Austria, housing is quite affordable. The way it is achieved, like your plans, is not yet possible in the US, because it relies on a more socialist mindset.

Instead of taxing per year, tax up-frtont. This reduces speculation. If you sell within 7 years, there is an anti-speculation tax to pay. Commercial real estate owners (i.e. non-human beings) can only amortize over 50 years (2% a year). Foreign individuals and companies must justify owning more than 2 properties in a long process per each property. Limit or forbid short-term rentals, and/or require the same safety standards from short-term rentals as from hotels.

The socialist part that really keeps down rents is that the city of Vienna and Austria as a country build and rent flats, that compete with the private market. That REALLY keeps prices down.

The real problem with the US is unfettered capitalism. Whether real-estate, cloud computing or on-line sales. More protections for individuals is needed.