That's why you're confused. The definition isn't anything to do with what you like, I admire Atget and Evans work greatly, but neither are remembered as SPs. While there were precedents and exceptions, for candid photography the hand held compact 35mm camera was the tool that enabled street photography. I know how Winogrand did it. He pre-focussed and shot freely, only using the rangefinder if he had the opportunity. A 28mm lens allows you to do that. It's one of the reasons street photographers do not generally use a 50mm lens. People think because they're carrying a Barnack and a 50 like HCB they're street photographers. To get the depth of field and freeze motion with a 50 requires great light and fast film. Most of the time your subjects will be distant, or out of focus or blurred. You're unlikely to get a half body shot and infinity in focus on a 50, something has to give. I'm certainly not claiming candid street photography cannot be done on a 50mm lens, but there's a reason street photographers choose wider focal lengths. Shooting street on an old rangefinder camera means you will be pre-focused much of the time, or you're shooting portraits not candidly. I absolutely agree. Most current street photography is shot on smart phones.