Zero-sum is one perspective, but not one that I subscribe to.
Does your neighbor having $10b of stuff make you better or worse off than if than if there's $10b of stuff at the bottom of the ocean?
Image that the economy is a field of wheat. It grows bigger every year as workers become more productive and learn how to fertilize and water more efficiently. At the end of the season, everyone gets a chance to head into the field and collect some wheat.
Some people don't have any tools. They pick the wheat by hand. Others have managed to fashion scythes and can collect a little more. But, the kid who inherited $10b has a fleet of combines that race into the field and collect 75% of the wheat in a flash.
The economy (wheat field) grew bigger and everyone had a little more wheat but the $10b kid got way more than the others and can now buy another combine for the fleet to get even more next year.
Without some rational tax on inherited wealth, we will create (and already have created in the United States) a plutocracy.
Your analogy is so far off the mark on how wealth is created, it's laughable.
$10 billion in family wealth is almost never held in cash, it's invested in companies, land, and other ventures. Wherever an investment is made, people are put to work collecting salaries and benefits, generally speaking.
You've made a gross oversimplification, and a misleading one at that.
No, not misleading at all. I never said the $10b kid had cash. Obviously, wheat expires (cash) and would be converted into another form of wealth. In this instance, he buys combines which have to be built by someone. You might even say he's a job creator.
But.... and this is a big but.... all investments are not job creating investments. Financial services, speculative investments, automation and robotics that increase worker efficiency but reduce the number of workers. I would argue that the efficiency of $10b in capital in the hands of a single person is far, far less efficient than $10b distributed across many people who use it to consume goods directly. The control of wealth by a small group produces a system where the rules favor the wealthy minority at the expense of the less wealthy. You can only go so far before the guillotines come out and the people take matters into their own hands.
Someone comes in with a tractor plough and plants twice a much wheat as last year. There is now lots of food in the economy and bread and pies.
In fact, the tractor plough plants so much wheat year after year that a few of the farmers stop planting and start working on building and maintaining tractors.
Eventually the tractors do well enough and wheat is cheap enough that the some farmers can afford to raise wheat-fed cattle.
It's also a problem if you view it as a symptom of a system that isn't functioning well at giving everyone a fair shake in life, in participating economically or politically.
The number itself isn't a problem, it's what it causes and what it's caused by that's the problem.
Get money out of politics, get everyone a vote and the capacity to use it, make sure everyone's fed and housed adequately, everyone has access to health care and education ... make it so we're living in a Star Trek TNG universe, and I don't care about how much the next guy has either.
Until then, it's worth looking at, at least the very least to help us to see why we don't have all those nice things.