It is impossible to be doing street photography today in the same style as Winogrand did 50 years ago. It is not the same type of game any more. Ned Bojic' answer is to the point (however, I would not say that the US were a happy place back then, there was still optimism /the American Dream, but that illusion had started to get shattered by the end of the decade).
Also, our streets have been cluttered by visual noise and awful, cheap, computer typeface shop signs or street signs of any kind with garish colours. Plus, the clothes people wear now keep them apart and not integrated with their environments. All these and also the way that everyone is so conscious about the representation of their own "image" that makes authenticity disappear, nothing looks spontaneous, genuine and interesting.
I really believe that photographers like Meyerowitz have had an easy ride, living in times where it would be enough to just point the camera at something and you would get an interesting enough picture, most of the time, because there was some coherence and even narrative in the visual perception of reality (that sounds too pretentious, but here it is).
Another interesting example for me is R.Depardon's "Manhattan Out" book - which I really like - where he is walking around Manhattan in the winter of 1979 (I think) and he shoots from the hip (he did this as a means to cure himself of his depression) but he never wanted to publish the pictures because he didn't think they were that good. I don't know why he now changed his mind (money?) and he agreed on publishing these "rejects" but they really look interesting, compared to what you would get today if you went around shooting from the hip.
Just my opinion, like the Dude would say.
