General Discussion

I assumed the facts supporting my statements regarding weakening of unions and laws that facilitated, rather than countered concentration of wealth, were widely known, but if not, here you go

Laws that have weakened unions since the 1950s
Taft-Hartley Act of 1947
Landrum-LaGuardia Act of 1959
State-level "right-to-work" laws that diminish collective bargaining power.
Deregulation and lax enforcement of labor laws have indirectly weakened unions by empowering anti-union employer practices.

EPI
Explaining the erosion of private-sector unions
How corporate practices and legal changes have undercut the ability of workers to organize and bargain
https://www.epi.org/unequalpower/publications/private-sector-unions-corporate-legal-erosion/

Tax law facilitating concentration of wealth and wealth inequality

Reduction in Top Marginal Income Tax Rates:
Top marginal income tax rate was 70%. in 1980
Economic Recovery Tax Act of 1981 lowered this to 50%,
Tax Reform Act of 1986 further reduced it to 28%.
Subsequent acts adjusted this rate, but the general trajectory remained low, sitting around 37% by the end of the period.
These cuts provided massive annual tax reductions for the wealthiest individuals, allowing them to accumulate and invest more income, thus increasing their wealth.

Preferential Capital Gains Tax Rates:
From the 1980's through 2025, capital gains tax rates remained low compared to historical levels and ordinary income rates. This allowed the wealthy, whose income largely derives from capital gains, to grow their fortunes much faster than average wage earners, whose income is primarily from labor.

Weakening of the Estate Tax:
The estate tax, designed to prevent the formation of dynastic wealth, was significantly weakened through changes in exemption levels and rates over the decades. This has allowed larger fortunes to be passed down through generations without being subject to substantial taxation, entrenching wealth concentration over time.

Tax Cuts and Jobs Act of 2017 (TCJA):
The 2017 tax bill included deep cuts to personal, corporate, and estate taxes that were heavily skewed toward the wealthy and corporations. Key provisions like the 20% deduction for pass-through business income largely benefited the richest business owners. These changes further eroded the tax burden on the top income brackets, contributing to the ongoing rise in wealth inequality.