First, I have to say, your English has greatly improved! I am very impressed.
Is it an economic problem, really? That there will be more billionaires? All these people with more money than they could possibly spend, kinda like today.Obviously it is cheaper to apply machines to a lot of repetitive labour and computers to even intelectual labours. You need less humans for that, so whoever owns the machines concentrates the power and resources. Scale it up and you quickly end up with a portion of people who have way more than they would ever be able to spend. Given limited resources since we are on a finite planet, that also means that a much bigger percentage of the population will be barely scrapping by, or actually struggling to survive. Is that the world we want to live in? Will it even be a safe place? Do you enjoy seeing other humans suffer because they don't happen to be born with a brain good enough for being a programmer? Should the rest of personalities become entrepreneurs? Is that fair to human nature? Or maybe the rest should become self-sufficient farmers? Except that billionaires are buying vast parcels of land that they will never be able to use and putting armed guards to guarantee people won't trespass.
It is an economics problem really.
Today, we have billionaires, with way more money than they could spend, so they do what most people with too much money do, they invest.
Who cares if the same guy who owns a significant portion of Tesla also owns a significant portion of a thousand other companies? The companies still do whatever they were going to do, whoever owns them.
Yeah, he has more money, don't motivate him to ruin your life, he is abnormally capable of it. But so is the crackhead on the corner. The lesson I draw is to try not to motivate others to mess with me, not that rich people are evil.
So how is a future with more megarich a problem, again?