"Supernatural" really means "something we don;t currently understand." As our understanding grows, it stops being supernatural. Cars, light bulbs, and blessed air conditioning would all have been considered "supernatural."
I don't really agree with this. I think of supernatural as things that are beyond the rules of nature. Nature has a set of rules, like gravity, which give measurable and predictable results every time. The supernatural is supposed to denote that it is a subset phenomenon that
allegedly supersedes natural law and order.
I do agree with you that it is essentially a functionally useless term, insofar as to say that it is subjective.
The point is that one would not expect to measure the supernatural in terms that apply with nature. How much space does God occupy would be a meaningless term for something that does not even reside in this plane of existence or, in essence, is the totality of this existence.
So expecting people to prove God or disprove God via science is useless. In that way, it would appear impossible to either verify or falsify God. In that sense it may seem reasonable to be atheist, but it also seems reasonable to be an agnostic.
There is no "supernatural" vs. "natural."
There is only "well-understood" vs. "not well-understood."
Maybe, and that's the point. We don't know, hence the apprehension of defaulting to a de facto position of either theism or atheism.
One might look at the supposed demon possession in the bible and conclude by today's standards, that those people who were claimed "possessed" where actually paranoid schizophrenics. But we don't know that. It's okay to be skeptical, but is it okay to say that couldn't be true because I've never seen anything like it?
This is precisely why these philosophical questions about God never end. If you really contemplate how much thought has been given to the concept of God, it's an endless debate.
The only thing we can conclude at this point is that it is neither verifiable nor falsifiable; hence, agnosticism.
"Men never do evil so completely and cheerfully as when they do it from mistaken conviction." — Blaise Pascal