I think the main reason that (average) real incomes haven't increased much is because of the decline of the unionized industrial/manufacturing economy here, and the rise of the non-unionized service economy. Almost all heavily unionized fields, outside government (teachers and others) have declined.
Indeed, and what can a teacher do if the unions that represent those teachers are unable to secure higher salaries? There's not a whole host of alternatives for a teacher who wants to quit.
As for any photographers left in the industry - what do they do when gigs refuse to pay the once going rate? And as the gigs themselves vanish, it becomes even more difficult to survive. For all the various causes already discussed to death, it has turned into a race to the bottom.
I really think this will spread to all the professions apart from, perhaps, medicine. Even law will be simplified into the ticking of boxes, with the resulting blunt instument being the the only available answer to every dispute.
This may sound a bit OTT, but I'm not so sure. As I have made no new pictures for a while, I have not a lot to do with time other than listen to music and surf for interesting interviews. When my imagination runs dry and I can't think of one more photographer whose work I want to investigate anew, I switch on tv. Looking at that for a couple of hours is alarmingly depressing - of the BBC's offerings, only BBC4 seems to give me anything I might want to watch. The other channels are mind-bending drivel. Breakfast news has turned into a chat show for the kiddies. I sometimes run through everything the remote can click into life, and if that's what the world is looking forward to watching in its free time, there is little hope left for mankind, and every reason to think that humanity is racing towards a new serfdom, if not its own erasure.
You know, they - whoever "they" are - say one should never look back, only ahead. I disagree: only by looking in the mirror can one see what's been tossed aside in favour of false improvement. Just think of the High Street in your small town, and the hive of activity that is was during past decades. Of course, this only works if you were around in those lost decades; if not, you may imagine it was always as it is today: chartity shops; closed shops; betting shops and the surviving pub.
Rob