i'm not taking any issue with how anyone likes to shoot, especially when it yields the excellent results we've all seen. and i myself often shoot zone or hyperfocused, which works great, always has, always will.
but, again, i dont think FF DOF is a 'detriment' to street shooting. ray, you cited HCB, he shot FF and with cams that couldnt go to 3200, let alone 12,800. honestly, its just a matter of style, and when one shoots. at iso 400, one can shoot at f8 in 'daylight'--not bright sun, just regular sunny 16--at 1/2000. take that down four stops for dim light--like very overcast or late afternoon, and youre still at 1/250. you still have 1-2 stops more 'darkness' to get out of the cam at 400 and 2-3 at 800. all at f8 on FF, which with a 35mm lens gives you about 5'-15' or 8'-close to infinity DOF. i just personally have found very few instances where this was an obstacle to street shooting. i think its more a matter of what one is comfortable with given how, what and when they shoot.
yes, apsc will always give you one more stop, m4/3 gives you two, just not sure its necessary. were i OP, I would think itd be pretty hard to think about leaving at home both of the two best cameras out there, totalling thousands in equipment, to get 2 stops when street shooting. there are many really good ways to cook tuna, including not cooking it at all! ):