The tl;dr is that I think the Boomers got a little screwed just because of timing: by the time it was clear that they needed to save more, and tax-preferred cheap investment vehicles were readily available, they were later in their careers, and so lost their first decade of compounding.
First, we can debate how prevalent pensions were and were not, but there was clearly a significant trend away from pensions that started while Boomers were in the workforce. There was also a trend away from unionized/factory jobs that started probably in the '80s, which generally provided both pensions and good other benefits (e.g., lifetime medical care), and which provided decent, reliable jobs to men with only HS-level educations; and since that again started when the Boomers were already in the workforce, it wasn't as easy to go get that college degree and retrain for white-collar work as it was for those of us who grew up being told that manufacturing was no longer a "safe" plan and a college degree was a better path up.
At the same time, those who did choose to save for retirement did not have the same tax-sheltered options that we did; the idea of 401(k)s and IRAs certainly was not around, except for perhaps the select few who had lawyers and accountants to tell them about those sorts of tax shelters (I myself didn't even have a 401(k) option until 1995). Oh, and mutual funds didn't exist for the first @15 yrs +/- of their careers; you had to buy individual stocks, and you had to pay a broker like $600 for every trade -- and then when mutual funds did become more popular, they were available only through those same brokers and charged like 6-8% loads. My grandma always put aside 10%, but she put it in CDs, because that's what middle class people did back then.
Another trend was the prevalence of dual-income families. Again, this really began in the late '70s/early '80s, when the Boomers were already in their 30s and up. So Boomer women, by and large, didn't grow up expecting to work once they had kids, and so many did not have college degrees, and the ones who did were largely qualified for low-paid "women's work" (secretary, teaching, nursing). And then let's not even get into sexism; my stepmom was not allowed into the state law school in the mid-'70s, and when she graduated from a different school near the top of her class, she couldn't get a job at any firm. Not to mention that it was entirely legal to fire a woman when she got pregnant.
And then you have the stagflation of pretty much the entire 1970s, with a crappy economy for a full decade. So for many Boomers, their first 10-15 years in the workforce did not provide a lot of wage growth or upward potential, while prices were rising dramatically. We have data now that suggest that Millennials who graduated in the Great Recession are still behind their cohorts who graduated just a few years later, so it should not be surprising that a cohort whose first decade-plus of work was in a very poor economy had a harder time catching up than those before and after them.
And then finally, you have the beginning of the college cost spiral -- right when their kids were going to school. Having watched the manufacturing economy come tumbling down, a lot of Boomers advised their kids to go to college. But they grew up in a time when it was possible to work your way through, so the idea of "save for your kids' college" was not as ingrained as it is now, and when they started to pay attention, it was too late to make much impact. So they chose to take on loans to put their kids on what they saw as a better, more secure path.
At this point, you probably think this is a complainypants rant. It's not. I mention all of these things not to say Boomers never had a chance, but because it all affected Boomers' ability to save and invest, cheaply and tax-efficiently, during the first decade or so of their careers -- which is by far the most important decade in terms of future wealth given the power of compounding. If two people start investing in 1980, but one hits 65 and retires in 2010 and the other is a decade younger and retires in 2020, the one who retires in 2020 is going to have more than double his counterpart -- even if he didn't invest at all over the intervening decade -- simply because he could afford to let his money grow for another decade. The Boomers didn't have that extra decade.
Not to mention that the younger guy had better, cheaper investment options. I mean, we all talk about the value of saving in a pretax 401(k) over a Roth, and a Roth over a taxable account, and investing in low-cost index funds vs. individual stocks, and the market over a bank account/CD, and so on. If a Boomer had say $2K to invest in 1975, it would most likely go into a CD, where it would sit and not compound. Or if he was sophisticated and wealthy enough to invest, he'd call his broker and pay about $600 to put the remaining $1400 into an individual stock, which might or might not survive the next couple of decades. Or if he had a mutual fund available, he'd pay another maybe 5-6% for the load, and then another 1-2% in management fees every year -- not to mention paying taxes on the gains every year. That's a lot different from someone who could put $2K into VTSAX in their 401(k), you know? So in the new world of 401(k)s, VTSAX, and disappearing pensions/medical insurance, Boomers started out behind the 8-ball just as a virtue of their bad-luck timing.
Does this mean that Boomers were just screwed and could never succeed? Of course not. Boomers still had thirty years, including the longest bull market in history, to save and catch up. And those who figured out how to save and live frugally are generally perfectly comfortable now, barring some external event out of their control. But when you are talking about bankruptcy, you are talking about people at the edge here -- the people who didn't have the skills or ability or knowledge or mentality to adjust to the shifting economy; people who maybe got caught in layoffs or had to change/downgrade jobs because of the changes in the economy; people who were/are raised to be leery of the stock market; people who weren't raised with the same "you're on your own" expectations that I was raised with. So given the timing of this constellation of events, it does not surprise me that a higher percentage of Boomers managed to save too little, too late, and take on too much debt, than the generations before or after them. Which, in turn, means it is not surprising at all that more Boomers would be on the edge and would drop off into bankruptcy.