Your comment really resonates with me, even though I'm nowhere close to a millenial. I graduated in 1993, into a pretty bad recession. It was very difficult to find a job, though (as usual) engineering grads did much better than humanities majors on average. I ended up doing a series of jobs that allowed me to survive financially, but did almost nothing to forward my career. I eventually went back to school to pursue a degree that would lead to better employment.

Fast forward to 1998, when the dot-com boom was going on, and it was an astoundingly different situation. I finished an MS (in engineering) and entered the workforce, but I really can't tell you if it was the degree or the timing, because college graduates with degrees in Art History and no experience were having a vastly easier time getting jobs. They didn't pay as well as engineering, typically, but they weren't stuck at the rental car counter or the coffee shop. They were getting jobs in marketing, sales, that sort of thing. Although the market crashed badly a couple of years later, I think that the few years of experience may have made a huge impact compared to people who graduated into the earlier or later recessions.

Seriously, I wasn't all that much older than these 1998 graduates - maybe 5 years or so, but the difference in experience was striking. And here's the thing - it can be lasting.

By going back to grad school, I managed to get myself considered a "new grad", though I was on the outer edge, age-wise, of this cohort. But without this? I would have been someone applying with jobs, with 5 years of non-relevant work experience. Some employers will be understanding, but they typically go to recent grads for the "zero experience" jobs.

During the meltdown that followed, I saw the same thing - recent grads in bad shape. I'd say the difference for the humanities majors is greater, because work experience makes such a difference. An engineering major will usually manage to get something that puts him or her on the career path, even if isn't the easy pickings it can be in boom times. But to a humanities major, it can be the difference between 5 years doing career-oriented work in the marketing department of 5 years stringing together coffee shop and dog-walking gigs. When that 5 years is up, they'll be at a disadvantage to new grads. And if you graduated into a boom, you have a much better chance of clinging to that marketing job, or getting one of the few ones that come available, because you have an incumbent advantage or even just a whisker of experience that makes all the difference when there are far more applicants than positions.

All of this has me very sympathetic to "cohort disadvantage". It can be somewhat generational, but I suspect that it actually happens dramatically even within generations. In short, graduating with an English degree in 1998 rather than 1993 can actually make a very big, and very lasting, difference in a career. It makes a difference for engineering majors as well, but it's the people at the margins (like the humanities majors) - where it can really go either way, where the starting point in that vector field really impacts the y-value 15 years later on that x-axis.

As a side note, I also read that grads of very elite schools are also less likely to suffer from the cohort disadvantage. Again, my guess is that this is probably because, like engineers, they don't end up on the wrong side of the vector field - they may not get their ideal choice of first job or move up as quickly, but they tend to get enough of a foothold that they don't end up on the other side of a brick wall - as a result, when the next boom happens, they are positioned to take advantage rather than getting left behind. There's also a good chance that they have access to a vastly a better network (say, harvard grads) to get back in even if they have floated a bit for a few years.