I felt better after reading a study (can't recall the source) showing that in most sectors and professions, income tends to peak in the mid- to late-40s, plateau for a few ears and then actually slides back slowly until retirement. It is apparently not the case that most people just keep making more and more until they retire.
I wonder if that study was actually tracking individuals, or just doing an average.
I can't see too many people staying in the same job and taking a pay cut. I know it happens, but it's news when it does. More commonly, it's like my case, you just stop getting raises. It's a pay cut when considering inflation, but it sounds like they were talking about a true pay deduction. It's possible I wouldn't get another raise for a lot more time unless I get a promotion, and it'd be a big jump in responsibility, effort, and visibility for me to get to the next level, so I'm not working towards it.
I can also see taking a pay cut when you switch jobs. If you get laid off or just want a less stressful job (maybe want off the management track), you might take a new job that pays less. But there's plenty of people who take a new job because they will get paid more, so I'd think that'd balance out somewhat.
If they are taking averages, I could see that some high wage earners are more likely to retire early, and when they leave the workforce it drags down the average salary in their field. So in a given field at age 60-65, you are likely to have a higher % of plodders who are in the lower range of the income bracket (no offense intended to any still hard working people here in their 60s--I'm certainly not saying that's all that's left).