> If you had progressive taxation that would essentially prevent any entity from acquiring power to rival the state.
We have progressive taxation. That doesn't matter because fixed costs are fixed.
If it costs $30,000/year to live, someone who makes $30,000/year will accumulate no wealth even if you tax them at 0%, because all of their income is going to food and rent and utilities. Whereas someone who makes a billion dollars a year will accumulate wealth even if you tax them at 90%, because the remaining 10% is still a hundred million dollars and after you subtract out $30,000, or even $250,000, there is still nearly the entire hundred million dollars left. Then that hundred million dollars collects interest every year going forward.
Trying to use taxation also ignores that the problem isn't actually billionaires. Corporations have more money than any individual, but the largest ones are publicly traded, so that would still be the case even if no individual shareholder had a lot of wealth. Because the corporation would, and its executives would thereby be in control of those resources and use them to capture the government.
It also ignores that you don't have to be a single entity to capture the government. For example, many professional licensing requirements purposely take a long time to satisfy (e.g. multi-year apprenticeship requirements) to create barriers to entering those trades. Not because General Electric wants to limit the supply of electricians, but because local electricians do, and together they represent a significant voting block. Landlords and homeowners capture zoning boards to inhibit housing construction, not because any of them individually have a monopoly, but because they all want housing prices to go up at the expense of people outside the local jurisdiction who have been priced out of the local area by the zoning restrictions and thereby don't get a vote.
> If you look away for a second, there is going to be some corporation trying to re-write the tax code or do away with regulations.
Why is it that the largest corporations and most corrupt organizations are the ones asking for regulations? DMCA 1201 wasn't enacted out of popular demand. The National Association of Realtors hasn't been lobbying to relax zoning rules. The telcos are the ones who want those laws prohibiting anybody from competing with them. Certificate of Need laws don't exist for the benefit of the public.
Corrupt regulations don't exist because of oversized corporations, oversized corporations exist because of corrupt regulations. If the megacorps didn't exist, all it would take is for some small organization with contacts to a powerful legislator to get something snuck into a bill, and soon the small organization is a megacorp with the power to keep those laws on the books. There were no trillion dollar corporations in 1913 or 1791, but there was Congress, so we don't have to wonder which came first.
What you need is to constrain the legislators from passing those laws to begin with, regardless of whether they start off at the behest of a billionaire or a trade organization or just the Senator's brother-in-law.