Yes, but "air" is not really comparable, is it? You'd never find someone saying "if we remove the wall from this room, we can make an air", or "you have your air, I have my air, and we should connect them to the Air".
There can be (and are) multiple internets. Hundreds, thousands of internets. There is only one Internet. The people who decide the nomenclature of the technology should be the network engineers who have the knowledge to build it. People who argue for "internet" don't seem to understand how internets work.
"The bug in the jar is running out of air" c.f. "Don't pollute the air" (i.e., Earth's atmosphere)