When Gene Smith shot "Spanish Village," the process was as high-tech as reportage of the day got -- international phone calls and all. Likewise much of the material you cite.

Because of the pace of magazine work (as opposed to newspapers and spot jobs), the photographers got a chance to work on a story for a while. You can still see this in (usually color these days) magazine work -- check the usual PoY sites, VII or Magnum bureau sites, foto8, etc.

Today, B&W has an iconic role that a PJ is usually best to ignore (if possible). You should not try to recreate Gene Smith any more than a musician should try to be Buddy Holly -- perhaps as a novelty act, but probably not as an original voice. That said, the strengths of B&W photography can still be employed in PJ work. It's my opinion that B&W tends to stress the "moment," the narrative aspect of events, more strongly than does color -- color is so good at raw description that it can overwhelm the emotion and event (this is not a universal characteristic, of course -- there are some great color PJ works!)

An extra spin is that a dozen rolls of Tri-X and an M3 are going to be far more effective than an analog or digi color kit, when on a two-month shoot in the middle of Lower Boonswaggle, New Guinea, where there's no lab, satellite uplink, fresh batteries or even electrical service. Color film will die in the climate and the digi... you know the drill. Obvious modern examples can be found in Salgado, Peress, Jason Howe, et al.