The difference today is a much larger economy. If everyone was still farming, there wouldn't be such differences. Should we "fix" that and return to farming?
In the 1900's most people weren't farming - and there were poor and rich then as well. It was the era of Rockefeller, Carnegie and Vanderbilt, although the Vanderbilts peaked a little before 1900. But the gap wasn't as large; there wasn't nearly as much wealth concentrated in those upper echelons.
So what was different? One clue comes from Carnegie's work called "The Gospel of Wealth." It called on the rich to use their wealth to improve society, expressed support for progressive taxation and an estate tax, and pushed philanthropy. He also warned about charity that tended to keep the poor, poor. Some notes from his gospel:
- He noted that heirs of large fortunes frequently squandered them in wasteful excess and ostentatious living, and he decried that.
- He gave advice on how to distribute accumulated wealth and capital to the communities they originated from.
- He advocated death taxes for those unwilling to give back: "By taxing estates heavily at death the State marks its condemnation of the selfish millionaire's unworthy life. It is desirable that nations should go much further in this direction."
- He was strongly in favor of progressive taxes: "Indeed, it is difficult to set bounds to the share of a rich man's estates which should go at his death to the public through the agency of the State, and by all means such taxes should be granted, beginning at nothing upon moderate sums to dependents, and increasing rapidly as the amounts swell, until of the millionaire's hoard, at least the other half comes to the privy coffer of the State.".
It was, in other words, a polemic on using the money to improve the infrastructure that allowed them to become rich in the first place, in the hopes that others could follow in their footsteps. Both via governmental and private channels.
Nowadays, people who pay a lot in taxes and give away large amounts to charities are considered stupid, evil, and something of a sucker. Indeed their charitable contributions are often the foundation of various conspiracy theories ascribing a desire to "take over the world" through nefarious means.