Inequality is complicated, but not so much that a My Little Pony parody can't tell you about it.
But, of course, there's only so much you can fit into six minute disquisition on the causes of inequality, even one starring animated horses. Financial deregulation has also played a big part, as you can see in the rise of Wall Street within the top 1 percent. So has lax corporate governance that lets executives turn boards into rubber stamps for bigger and bigger pay packages. The decline and fall of unions has made worker's dwindling bargaining power even worse. And, to add an even greater degree of difficulty for low-income kids, they're more likely to be born to single parents and go to failing schools — turning inequality into an awful inheritance.
Despite all of this, it's important to remember that, to some degree, inequality is a choice. Now, it's true that big global forces, like new technologies that help white-collar workers more than others, are increasing inequality everywhere, even egalitarian Scandinavia. But it's also true that those countries still have much, much lower inequality than we do here, due to a combination of higher taxes, bigger transfers, and minimum wages that make $20-an-hour McJobs a reality. Government, in other words, really can bring inequality down to less Dickensian levels if it wants to. And, according to the IMF, it might not even hurt growth, like everyone assumes it would, if it did. In fact, reducing inequality might actually help growth by giving poor kids a better chance to develop their talents.
Or you could just go watch an Ayn Rand-quoting alpaca explain it all.