I think you're missing the point. I'm not arguing that those who have profited from the functioning of the economy owe something to the system that enables that economy to function well (regulation, road building, fire departments, standards bodies, what-have-you), that's an entirely separate argument (and a good one at that). I'm arguing that the vast majority of "the rich" have, in some sense, cheated their way to that wealth, period. I'm saying that they have used the power they have gained from their wealth to take advantage, and take money that is not deserved. Money that would not be theirs if we lived in a fantasyland world where markets were perfectly fair and efficient, where regulatory regimes where incorruptible, and so forth. We don't live in such a world, our world is messy, our world is one where there are numerous advantages and numerous lines of corrupt influence that flow from being in positions of power and wealth.

And we would be fools, utter fools, to deny that, no matter how much we treasure the ideals of free market economies. In fact, if we do value the free market we must be aware of these things, because they are a major reason why people might fight against the model of the free market and they are a major corruption of the ideals of the free market itself. Regulatory capture, for example, is very much an enemy of the free market, but it very much exists, and pretending it doesn't won't make it go away.

As such the idea that taxing wealth is necessarily "theft" is ludicrous. Not only can it be seen as a "fee" for being allowed to operate in a civilized society with many robust services and infrastructure (the argument you seem to claim I'm making) but it is also a means of correcting the inherent corruption and unfairness in the system. It's a fudge factor that attempts to correct (via Kentucky windage) for the problems that would otherwise require likely tens or hundreds of trillions of dollars of concerted effort (or more!) to fix properly to any reasonable degree. So in lieu of spending significant fractions of the world's GDP it's vastly easier and at least somewhat effective to simply engage in wealth redistribution.

Let's look at some facts. We know that wage theft (where employers illegally avoid paying employees what they are due) exists, and accounts for a few tens of billions of dollars in lost wages every year in the US alone. We know that discrimination (based on race, gender, religion, sexual orientation, etc.) in employment and housing exists. We know that many instances of health and safety violations exist in many corporations across the world on a daily basis. We know of many examples of predatory business practices (such as predatory lending, municipal fine collection, etc.) that have bled money out of people in poverty. We have seen consistent weakening of labor laws and union power. We know that corporate tax breaks and corporate welfare are widespread at all levels of government, to the tune of hundreds of billions of dollars a year in tax revenue. All of these things are instances where people at the bottom are being unfairly taken advantage of while money is flowing into the pockets of those at the top. Look at the VW emissions scandal. Where a company violated the law across numerous countries in order to line its own pockets. And the consequences of that? Likely a significant number of deaths due to emissions levels higher than they should be.

Again, it's impossible right now to fix every single one of those problems, but those problems still exist, and in many cases they are becoming severe enough to weaken the very foundation of our society. These problems are the reason why people in the UK voted for Brexit, they're the reason people turned out in droves for Bernie Sanders and for Donald Trump. They're a big part of the reason why there has been an unprecedented increase in the mortality rates of white, middle aged Americans over the last several years, in contravention of all accepted wisdom about advances in medical care and so forth. The public is not always going to respond in the best way possible to these issues, because for the most part they don't fully understand them, but they do feel the pain, and sometimes that will result in them latching on to anyone or any cause that proclaims to explain their pain and offer a solution.

As to your model, again that seems to rest on the theory of the fairness of the economy. Natural accumulation of wealth is an issue, certainly, and there are good and bad aspects to it, and the bad aspects need to be countered. But I'd say that's a second order problem compared to the one we're facing right now.

There's this old saw about "the rich getting rich and the poor getting poorer", and for much of the industrialized age it wasn't actually very true. The rich got richer, but the poor got richer too, as the pie got bigger. For the last 4 decades the pie has continued to get bigger as well, but the rich managed to not only take their (also growing) slice of the pie, but also take some of everyone else's slices as well. And we've stumbled into a state where the poor are actually getting poorer even while the whole economy grows by leaps and bounds. And a state that has persisted for more than a single generation as well. That's untenable.