Looking at IRS data, top 1% tax payers in US in 2018 paid 38.5% of the federal income taxes. Bottom 90% paid 28.6%. So I don't think they're as good as hiding their money in the Cayman Islands as you think they are: https://taxfoundation.org/federal-income-tax-data-2021/

In comparison top 10% of the Danish tax payers paid just 31.3% of the total income tax, despite Denmark having rather high taxation (the OECD method that puts it as #1 is controversial, but I pay e.g. a 42% marginal tax rate on any capital gains).