Nowadays, the housing is one of the main problems around the biggest cities. It also a problem in popular areas with a non-development plan. Moreover, green areas are an important resource in terms of quality for a city. These are mean, I disagree with the idea to replace housing for parks. Both should be considering a priority for a city and society.
Governments are responsible to frame the priorities and solutions to these problems. Housing lacks began because is a business and there is not any law or frame that helps equal to tenants and owners. Owners want to get the most money they can and tenants can not afford the “free” price that markets allow. Airbnb is an example in these days. Owners prefer to rent them properties for short term and with higher prices than long term and cheaper prices.
It would be a great idea that governments create different laws to regulate the market and give a fair solution to both parts.
Furthermore, a fair regulation would fix the housing problem. Instead, to discuss the use of green areas. They are necessarily around every city. They create a healthy ecosystem, they allow people to enjoy, to training, to gather, etc.
In conclusion, my experience around the world is that cities with a regulated market and with a lot of parks are the cities healthier and more expensive. But i believe that is not happen almost anywhere. The system, the money and the corruption are a bad combination to get effective results for the people.