You are clearly confusing a legal requirement with a good practice. It's absolutely a good idea to get a model release and I'm not trying to suggest otherwise. However it's mostly required for editorial and advertising photography because the potential lawsuit risks are so high (and typically people doing advertising have the dollars to be forced into big payouts).
Go read up on Arne Svenson - he shot artistic photos of his neighbors through their open windows. A lawsuit against him was dismissed last year and the judge said ”An artist may create and sell a work of art that resembles an individual without his or her written consent".
The Svenson case is even more egregious because it covers photographs taken without any consent (written or otherwise). I see why it's an obvious target but I don't think changing the rights of photographers and other artists is an appropriate response to this.