Is it possible? Of course. I would argue that one have been sold way too many times the excuse that you would fare better with smaller cameras, like the Leica.
Vivian Maier shot on a Rolleiflex, a twin lens system that is so much harder to focus and looks pretty weird when you have two lenses pointing at you. Back then people knew it was a camera and there is nothing in that form that contributes to her infamous photos.
Leica rangefinders are louder than most of the Olympus, Fujis and Ricoh GRs that exist in the market and probably the largest of them all. Still we have current credible photojournalist and photographers that swears by it for street use.
The answer is really our own acceptance of what we are comfortable with. A medium format camera should not prevent you from doing street photography.
If you prefer B&W cause it has more soul or captures someone’s soul (darn are we back in the dark ages) , a medium format camera like the Pentax 645z gives you beautiful gradation and smooth tonal dof transitions.
Make your own decision. I personally had a lot of fun shooting and using a medium format camera like the Pentax 645Z for portraits and streets and I am convinced that the suitability of any camera is defined by you.