Even if producing a record supply of housing units could guarantee solving the affordability issue, actually building that much housing with viable density comes with a steep price tag. Even advocates of mass housing admit as much. If we don’t go after the land value itself, we are essentially trying to deflate a balloon by blowing on it.
Capitalism is imperfect, but business owners actually do at least carry some amount of upfront investment and risk. These things are obviously still true in housing (and food production/distribution and healthcare in the US) but they are captive markets. People need a place to live, need to eat, need medicine. This need allows unreasonable extraction of wealth because people can’t choose to just not partake.
When building housing, it is often the municipalities that fund the roads, cables, and pipes run to the neighborhood. For this reason, housing developers carry very little risk and have very little incentive to choose a type of housing with long-term economic sustainability. They can pick a development pattern which will cost more to maintain than it will generate in tax revenue for the city and sell it for a massive short-term profit because they only need to care about the housing market, not the infrastructure that supports the housing.