~
I was just getting ready to respond, and then I read your post, where you pretty much said everything I was going to say

becoming reliant on our scientific advancements
This is not new. Photo below of 45,000 year old mammoth bone with spear wound. The history of human civilisation is the history of tool use, is the history of using technological advancements to keep ourselves alive. Vaccines are a triumph of human ingenuity.
http://siberiantimes.com/science/casestudy/features/f233-the-smoking-gun-proving-ancient-man-killed-woolly-mammoth-45000-years-ago/I don't know what you think about the role of vitamin D in all this.
The evidence I have seen seems to suggest that a deficiency in vitamin D can make COVID worse, rather than extra vitamin D being protective against COVID, but I haven't spent a huge amount of time reading around this topic. Regardless, the majority of Americans are deficient in vitamin D, especially those in more northern states, and should be taking a vitamin D supplement anyway.
Yes, moderate supplementation seems like a good idea, especially at higher latitudes. I'm not sure how likely toxicity through overdosing is, but ultra-high dose vitamins aren't a great idea in general.
In the UK, the NHS
has been offering free supplementation for Covid high-risk groups. There's also a recent report by the BMJ
here.
It's worth noting that vitamin D is
not a secret magical panacea that is being hidden from us by Big Pharma because it doesn't make them $$$. It's also worth noting in regard to this myth that AZ are providing their vaccine at cost, with no profit motive.
Vitamin D may help against Covid to an extent, and is unlikely to harm unless you're mega-dosing. But it's not the single answer, or even the best answer. Vaccination is the way out of this. And until vaccination is at sufficient levels to provide herd immunity, then masks, social distancing etc are crucial.