Let's take it one sub-section at a time, starting with Part D:
The most insane "free give away" of younger tax-payer money, which the first decade of beneficiaries effectively contributed <10% of received benefit (prescription drug subsidization, but only if you're retired/disabled).
I am ALL FOR SINGLE-PAYER HEALTHCARE SOLUTION — I dropped out of a US medical school over a decade ago (realizing the system then was broken, most-obvious-then with the passage of medical student / resident ~80hr/week MAX scheduling (ha ha ha)). Obamacare was doomed before it even passed, and I personally paid the IRS "fine" for the few years required.
Your wall of text is absolutely spot-on, breath-taking!, and yet I recommend to many to embellish their lives in facts, starting with the greatest book [1] on Modern US Retireeism's Upper Crust [certainly there are numerous more impoverished Boomers]; those that did from the "I got Mine!" Generation absolutely are detached from the reality of modern US Decline [opportunies aren't there, folks, for massive segments of population].
Some common examples I see in my part-time philanthropy work (medical focused, for underserved populations within US):
Rich, Well.Meaning Donor: "Yes, but I'd rather donate mother `internationally` because there is SO MUCH OPPORTUNITY FOR US CITIZENs to work and they `just aren't` working."
Donor coordinator (not wealhty; work is matching tax-writeoffs with approved local charities): "That is JUST NOT THE CASE, Friend [2]. I am happy to discuss the complexities of any of a variety of hindrances which keep the majority of Americans impoverished, renting, and unable to develop their own Generational Wealth — pick any topic"
Rich Phil./Legal Tax Avoider: "Why doesn't anybody want to be a non-traveling nurse anymore?!" [==contract nurses that rotate positions and are very. well. paid |VS| full-time staff nurse]
D.C: "Because working staff at a hospital doesn't pay very well, for all the emotional and physical BS that nurses have to deal with -- and the hospital gets gutted by some MBA/JD that works quickly to make each Fiscal Quarter more profitable, to the ultimate doom of the healthcare of patients and well-being of employees. By being short-term traveling contract, only, the MBA/JDs [at first] appear to be saving money [i.e. more shareholder value!] until ultimately the cost of mismanagement/lawsuits from overworked staff and misunderstood wards ends up destroying the entire healthcare system."
Rich Donor, less gratuitously: "???" "But USA has `best healthcare in the world!` ... `wait times` ... `yada` ..."
Me: "...if you can AFFORD IT."
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[1] book "A Generation of Sociopaths" A+
[2] e.g: RAM (Rural Access Medical?) started out as an international charity started by a US Physician... who then realized that underserved/uninsured US Citizens oftentimes face 3rd-world-like health crisis, particularly in rural Appalachia (for just one 5M+ example!).