Suppose you attend an Ivy League school, getting honors in computer science. You get a job at Google. You make, roughly, $100K per year. You have plenty of food and a nice apartment, but you don’t live luxuriously. You probably aren’t much richer than your parents. You might think, therefore, that you’re basically an Average Joe. You have a nice job, but you’re basically just another guy making a living.
But wait. Let’s use math. About 0.2% (1 in 500) people attend the Ivy League. Within that group, only a minority major in something technical, and only a small fraction of them get honors, if honors means anything. Defining “ability” as a scalar is tricky – it has many components – but for most reasonable weightings, you’re in the top 0.1%. Now, looking at income distribution, top 0.1% means making millions a year. It means you can buy a house in the Hamptons and a private jet. Of course, you don’t have any of that. But why?
The main reason is wealth increases dramatically with age. Not just by a factor of two or three, but by orders of magnitude. The reason you don’t feel particularly special, compared to average adults, is that they’re thirty years older and get enormous advantages from that. It’s like running a marathon with a big lead backpack – you’d have to be at the top to compete at all.
Projecting forward, then, when you take the lead backpack off – when you’re a few decades older – you have a good chance of being in the top 0.1% elite, the private-yacht-party-jet crowd. We can make a pretty ironclad argument:
Assumption 1: The US economy will keep growing, or at least not shrink dramatically.
Lemma 1: There will, therefore, be at least as much money and goodies around in several decades.
Assumption 2: Income inequality will keep growing, or at least not shrink dramatically.
Lemma 2: Since there will be at least as much total stuff, and the rich will have at least as large a share of it, the rich will have at least as much stuff.
Observation 1: A large fraction of the Ivy graduates of yesteryear are now global elites.
Observation 2: The Ivies are doing a decent job of selection – relative to decades ago, those admitted aren’t especially lazy or stupid.
Lemma 3: A large fraction of today’s Ivy graduates will become global elites.
Conclusion: Since a large fraction of Ivy graduates will become global elites, and since the global elites of tomorrow will be at least as wealthy and powerful as today’s, the average Ivy graduate today has a large chance of joining the private-yacht-party-jet club when he becomes older.
The Rationalist Conspiracy 
Right as usual, but some counterpoints
> The Ivies are doing a decent job of selection – relative to decades ago
I’ll grant that it’s better than the good ol’ days when Dubya got his gentleman’s C.
But read Golden’s “The Price of Admission” to see how the Ivies favor legacies, athletes, famous kids, kids of the famous, a few wealthy minority students, and kids of donors.
If, as some suggest, the social-signaling value of college is about to crack under disruptive technology, you may find that your Ivy degree is as valuable a signal as a dukedom in post-Industrial Revolution England, and your personal outcomes may be similar.
> A large fraction of today’s Ivy graduates will become global elites.
Yes, but even the top 0.1% of ability (granting the dubious proposition than these Ivy-ers are in that group) will not automatically become the top-0.1% elite. Motivation and luck are involved. MOST of the people you mentioned will stay roughly in the “upper middle,” e.g., continuing as professionals or middle managers. (The ones you NOTICE in 20 years will be the few who hit the 0.1%-elite.)
The Ivy people just have a BIGGER chance than others of hitting the top elite, both because of abilities and because of current societal conventions.
> the lead backpack
That is a quite unreasonable metaphor. The youngsters have no more lead backpack than the oldsters had in their day. A better metaphor is that the older rich are way ahead in the race, because they started running earlier!