Capitalism takes several basic realities into account:
1. Greed is human nature.
2. There will always be poor people.
3. Nothing is free.
4. Nobody is entitled to anything.
1: Most people are greedy to some extent but some people are more greedy than others, and that can be shaped by e.g. their environment/upbringing. Society shouldn't embrace it but strive to minimize it in favor of altruism. Parasitic greedy activity which is let loose in a free market should be punished, but people should still be rewarded for hard work.
2: Different countries have very different fractions of people who are poor. Even if it were true and it's not possible to fix in the future with better technology and a better system, there's a huge difference between 0.001% of a population being poor and having a working class which works all day yet is still poor.
3: I don't see your point here.
4: Let's go right ahead and take away all that wealth the capitalists were never entitled to then.
It also relies heavily on the idea of "caveat emptor," or "buyer beware." If a big business (or "bourgeoisie" as good ol' Karl put it) is corrupt and untrustworthy, the solution is to not do business with them. If they extend into the government, don't vote for them. Term limits on congress members would help a lot.
It sounds nice in theory but it's not happening in reality. USA and Europe have only gotten increasingly corrupt over the past 30 years with capitalists increasingly lobbying and interfering in politics. I wonder how one would even stop doing business with so many morally bankrupt companies people's every-day lives rely on. I already avoid Nestle, Coca Cola and some others, I changed bank, avoid certain clothes, but I can't spend my entire life researching the ethics of every company, and there are many areas where none of the companies are ethical - most people are simply too apathetic or take too little time to make your idea work. And I wonder how in USA, you would get a new system when capitalists have taken over the Democrats and Republicans which pits most people to vote for either just to avoid the other worse alternative.
The elite class still has to work in order to keep the business managed and functional. They don't just sit around doing nothing.
Most of the elite does work, but not an amount that entitles them to 100 or more times the income than the workers who spend 60 hours a week in a factory or similar. The capitalists mainly get their ridiculous wealth by taking a part of the value created by the workers, that's parasitism.
Alternatives to the capitalist system tend to be even more broken for the same reasons. Even with today's popular "democratic socialism," a bourgeoisie builds up over time as the population grows.
A big government is no more trustworthy than a big business. They tend to parallel each other.
I live in Denmark which is less capitalist than USA, and I'd say USA is more broken. I don't see a tendency for alternatives to capitalism to be broken for the reasons you gave. USA and Europe or their companies has plundered and colonized half the world to get their wealth. Many third world countries are also capitalist and have never succeeded. Many countries trying socialism have historically been poor before socialism but then been isolated and attacked by some of the rich capitalist countries, or stagnated because of an arms race with them. There's complex reasons behind it all, not simply things like human nature or nothing is free.
A big government has the opportunity to be under democratic control, which is a major difference from a big business. And if you ask which trades people trust the workers in more, in Denmark, they rank from 1-5 least/most:
4.04: Nurses
3.94: Judges
3.94: Doctors
3.81: Policemen
3.67: Soldiers
3.56: Dentists
3.51: School teachers
3.50: Home helpers
3.50: Teachers for children
3.37: Hairdressers
3.32: Bus drivers
3.31: Lawyers
3.26: Farmers
3.19: Craftsmen
3.03: Mechanics
2.86: Bank advisors
2.57: Realtors
2.46: Journalists
2.39: Car sellers
2.06: Politicians
http://radiuskommunikation.dk/wp-content/uploads/2016/11/Trov%C3%A6rdighedsanalyse-2016-Mange-faggrupper-oplever-stigende-trov%C3%A6rdighed.pdfMaybe because a public healthcare system actually works and isn't just there to convince people they need some expensive operations or medicine, unlike the bank advisors, realtors and car sellers who are there only there to get away with as many lies as are necessary to drag the most money out of the customer.