The biggest flaw with subsidized renting is that it drains taxpayer money from the treasury into the pockets of the privatized housing corporations and their (mulit-national) investors and shareholders.
Then again, it's better than suddenly having 1 million Dutch suddenly finding themselves homeless because there is no housing they can afford, but it should not be a permanent solution. At least not without nationalizing all housing corporations, or at least the social rental segment. Which IMO could be one solution. It was never a good idea to sell off city / province and state owned housing to the free market in the first place.
EDIT: ofcourse, it's really hard to compare US housing market to Dutch housing market. It would make more sense to compare Dutch housing market to City of New York housing market or LA housing market. Let's just say, any piece of land that has not had a building built on it is nature preserve or otherwise reserved for non-residential purposes. There's scarcity in all housing segments, from low to high. Now if only the housing corporations would build more affordable housing, but alas, most keep that to the bare minimum they get away with, and focus more on middle class housing and corporate prestige projects.
And then there's the problem that most middle class rental homes are so much more expensive than the social rental ones, that the social rental ones are clogged up with people who started out on low enough income to be allowed to rent there, but now technically earn too much, yet still too little to afford middle class housing.