I have had two decompression incidents. One as slf and one as a pilot. Both were on BAC 1-11s and that series of a/c was not permitted to fly above FL350 as it didn't have drop out masks for the pax. If my memory is correct we carried 17 masks for 99 pax.
The first occasion happened at TOD so we descended rapidly to 8000ft or so and then landed at LHR normally. Some pax were a little breathless for a while but there were no problems and the cabin crew did a good job of reassurance and nobody suffered.
The second time, having departed MAN we had just reached TOC near Woodley when both air systems failed. I could see LHR on our left so we declared an emergency when well in the descent and were aware of a white faced chief steward with his portable oxygen on standing behind us in the flight deck waiting for instructions. (That couldn't happen now!) We met the cabin going up at about FL220. Again, no problem really. A quick a/c change and continued with the journey. And of course nothing appeared in the media for either event.
I suspect that in yesterday's incident if the punters had put their masks on even if they were not aware of O2 flowing they were working. How many died of anoxia?