Wealth distribution

I came across the following image here a few days ago:

The above referenced link is to a story about the disconnect between Americans' belief(s) about wealth distribution in the U.S. and reality. Specifically, it says:

It's fine if reasonable people have different ideas about whether we should extend the Bush tax cuts for people making more than $250,000. Or think estate taxes are unfair. But when we have those debates, it's critical that everyone has a clear understanding of how things really are. We're becoming a plutocracy.

I'm not going to argue against that last sentence. Debating the merits of tax cuts for certain brackets or in certain situations in an effort to stave off a plutocracy, in my mind, though, ignores the bigger picture.

It seems to me that the dangers of a plutocracy lie, not necessarily with those that control the wealth, but with the government that can be controlled via that wealth. Specifically, there is very little that the U.S. federal government currently does not regulate. Under such a system, the aforementioned wealth can be very dangerous as it can be used to steer that regulation, which carries all the force of law, in directions that benefit only those controlling the wealth.

Contrast that with a government under which there is very little or even no economic regulation. In this system, plutocrats are not able to influence regulation to protect their wealth. They must simply produce goods and services that consumers are willing to buy; they must actually compete on the merits of their wares and business methods. The risk is that if they don't, other businesses will spring up in their place and eat their lunches, so to speak. Under such a system, consumers hold all of the power, and the "problem" of unequal distribution of wealth may work itself out.

I say "may" because, if we remove government from the equation, it's not immediately clear to me that the wealth distribution in the chart above is necessarily a problem. For example, the chart does not give the reader any indication that those in the lower quintiles do not have enough money to sustain their needs. Note that I'm not arguing that they currently do have sufficient money. Assuming for a moment that they do, though, and that there is no government to be influenced in economic matters, is there a problem?