Wikipedia is the 7th most visited website in the world, more popular than Amazon, TikTok, even PornHub. It's not funded by advertisers or other bullshit - rather through reader donations.
With that said, Wikipedia is still centralized content whereas Lemmy isn't. Meaning there's fewer expenses and pressure on any one instance or server to succeed. And if one instance or server doesn't succeed, your access to the Federation is far from over.
An individual can sign up for a plan through their State’s health insurance exchange or the federal government’s HealthCare.gov website.
It is usually more expensive than getting it through an employer - but works to serve small business owners, freelancers, etc.
A few States (like Massachusetts) have semi-universal systems that cover all individuals that earn under 150% of poverty, independent students, newly unemployed, etc.
A lot of Americans are also covered under Medicare, Medicaid , Social Security and other programs.
Retirees aged 65 and older are eligible for Medicare - a semi-universal federal system that covers pretty much everything and accepted most places.