I think there are some generational changes going on. For most of human history, of course, you worked until you died, and not being able to do the former generally led to the latter, barring inherited wealth, charity, or family to take you in. Then post-WWII we developed this concept of the single-earner, 9-5 job, work for the same employer until you're 65, and your company will take care of you for that first 40-45 years, and then your company/government will take care of you for the rest. [Assuming you were a reasonably intelligent straight white Christian male, of course, but that's another story]
But I think the story since then is one of promise after promise being undermined. First the steel mills and other manual-labor Union-type jobs went away, so the story for my generation was go to college and get an office job. Then of course the office jobs started going away, both through geographic arbitrage and technological efficiency. And all along pensions are being cut, SS is being trimmed (and frequently threatened with more), companies are doing mass layoffs as part of mergers that benefit only the executives and investors, etc. etc. etc.
The problem is that much of our economy was built on trust: the only reason a sane person would commit himself to a company for the long-term, work overtime to handle crises, and generally go above and beyond is because he knows they are committed to him. People will not devote 40 years, when they know that in year 39 you're likely to terminate their pension; they will not go to the wall for you when they know you just consider them to be Fungible Widget #87693; when all you want is the cheapest possible labor, all your labor wants is the maximum possible wage.
Which leads directly to the OP. Because if you can't trust the brass ring to be there for you later, then why in the world would you sacrifice now? It's almost like people are realizing that the rules of pre-WWII never really went away, and you're going to need to either work forever or find some alternative that allows you to opt out earlier -- but in any case, you're basically on your own. And people respond to that differently. Some are doing so via more current work-life balance (we have many associates, for ex., who don't even want to be a partner); some will work their asses off for a decade and save everything to go ERE; some assume they will have to work forever and so look for careers that give their lives meaning -- cool tech, for example, or teaching or charity work that helps people, because who cares if the salary is smaller if you're working your whole life anyway; and, of course, many will also assume that retirement is out the window but will then continue to work for as long as they can for as much money as they can so they can keep buying more stuff.
I don't think the actual picture is nearly this bleak, btw; there are a lot of idealistic people out there right now determined to change the world. But I do think the future is going to look very different than what my generation was taught growing up.