Coming in late to the thread, I'm just recalling when I was a shooter in the 1970s & 80s--mid-sized daily newpaper. Using Nikon F and F2 cameras with motors, the "lightweight" alternative was a Nikon F or F2 without the motor. Maybe a Nikkormat for some and, later on, the FM. Few newspaper photographers of my acquaintance at the time owned Leicas--they were already too expensive for our pay grade. I picked up an Olympus XA at some point to carry when off-duty (I still have a couple of those around here somewhere). It was carried a lot and used little. It was a "there" camera. Comparing the images of the XA to those from SLRs of the day was about the same as comparing pocket digital images to APS-C or full frame. They may not have been as good technically but they were good enough and--well, hell--you wouldn't have gotten the shot at all if you hadn't had a camera. Content was more important than technical quality.
Come the digital age. Emphasis on technology. Too much, methinks. Stanley Forman's blurry photo of the black man being beaten by a mob carrying an American flag may not even get published today, let alone win a Pulitzer, given such lofty demands for technical perfection. Lots of great news photographs can't stand up to being printed big but that doesn't make them any less great.
I wish the pocket cameras were a little more user-friendly for documentary purposes, as noted above. It's hard to use some of them in a reactive way very quickly. They are better than earlier models but not perfect. Once the work-around is figured out, they can be very effective--I think Bill has shown this to be the case with his use of the Canon G-series cameras.
The question asked concerns the pocket digital replacing the rangefinder for photojournalists. I think it already has done so, given the subject of the email Bill quoted. They are convenient, capable of good results and, more importantly, they are "there". Although I'm no longer a shooter, I still take pictures occasionally🙂 . I don't use my Leicas or my DSLR as much as I used to, I carry a Canon G-10 a lot and, sometimes, a Panasonic Lumix. The G-10 is a fine documentary camera and the resulting images range in technical quality from excellent to more than acceptable. (I still qualify "acceptable" as Tri-X shot at EI 1600.) The Lumix is not bad either but I don't find it's high ISO capability to be very useful. But it can still be "there".