The findings also suggest that who your parents are and how much they earn is more consequential for American youths today than ever before. That’s because the difference between the bottom and the top of the economic ladder has grown much more stark, but climbing the ladder hasn’t gotten any easier [....]

So I heard about this on MarketPlace today, and I'm having some trouble understanding it.

• So, it's just as hard or easy to move up as it ever was, but...

• But people start on vastly different rungs on the ladder by virtue of their family...

• So the differences are wider, but they don't get much wider or less wide over time.

If that's right, then how do those vast differences come about in the first place?

Let's eliminate scions of the Johnson and Johnson family who've had their money "forever."

Let's talk about someone like Jobs who went from being middle class to being a member of the .000001%. Maybe that's not included in the definition of "mobility." Maybe "mobility" is when someone "works his way up" and his son moves from there higher up on the on ladder. That's not what Jobs did. He didn't "move up"; he pole vaulted up over the ladder.

So maybe the 1%-plus are people who pole vaulted or catapulted themselves up over the ladder, and their kids start from that point and never move up much from there. They're born rich and they die rich. And middle class kids may move up, but they will never get anywhere close to where the 1%-plus are because of where they started. Sort of like being on a carousel; you move forward, but never close the distance between you and the horse in front of you.

Meanwhile, most of Jobs's friends from high school never found a pole vault or never created one, and they are stuck where Jobs would've been stuck had he not found his pole vault. Plodding along...and moving up maybe, but never coming close to where Jobs is.

So maybe the point is, our society is now such that there are ways for a few people to pole vault or catapult themselves up--like those 85 people who own more than billions below them--but that isn't really "upward mobility" because there's no clear path for people to follow to replicate that kind of dramatic jump in economic status.

So maybe the key point about "upward mobility" is that there has to be a reasonably clear path: You get a BA...you join the union...you get a factory job...you do XYZ and you will "move up." No guarantees, of course. But you don't need to be exceptionally smart or talented or lucky or ambitious to do it. Just averagely so. You just need to want to "get ahead" and have enough discipline and do the "right things" and you are likely to succeed and move up.

Move up to the next rung. Your kids will start from that rung and move up to the one just above. And so on.

So are the authors also saying that this sort of gradual upward mobility is still around and as easy (or hard) as ever, but the pole vaulters are jumping so high and so fast, it just seems like everyone else is standing still or losing ground?

Or are they saying that the pole vaulting is actually making it harder for the traditional step by step upward mobility to take place?

One of the things I wonder about is this: Conservatives will often ask, "How does it hurt me if my neighbor is 100x richer than I am?" In a way it doesn't. But then again, do those 85 people who own more than the billions below them make it harder or more expensive for those billions to acquire what they need?

If you think of a gentrifying neighborhood, you can see how a bunch of rich people moving in and paying a lot for homes can push prices (and taxes) beyond where the people already living there can afford them. So they're pushed out.

But this same thing happen across a society as a whole? Can a small group of people with an ungodly amount of money bid up the cost of living across a society in a such a way that it makes it significantly harder for those below them to afford what they need?