> Do you not think that stealing requires the original owner to lose access?

No.

> If I sneak into your home, take apart the coffee machine, measure everything, put it back together and go home and build a copy to have my own, did I steal your coffee machine?

Not mine. But the company that made the coffee machine. It is stealing IP.

> Can we not just stick to calling it copyright infringement?

It is just a fancy way of saying you stole someone's IP. You can call it infringement if it makes you feel good. But the act is the same end of the day.

I would not classify sunshine and air as "free". Sunshine requires the Sun to undergo continuous fusion. It is invaluable as opposed to "free". Air is invaluable asset too. Without both we would be dead. The price of both is literally price of my being alive every second of my existence.

Public domain on the other hand is legally only possible if/when copyright has expired. That means the owner has enjoyed proceeds from copyright protection for more than his own lifetime. That is fair. It is still not comparable.

EDIT: since you tacked on more like "wind, gravity, radioactivity" etc, I would still not classify them as "free". They are invaluable to very existence of life.

"Knowledge passed on" is also after someone (in ancestry) has paid for it through blood, sweat and tears. It isn't "free". "Public domain" is legally recognized form of "knowledge passed on".