Nobody wrote:

It intrigues me as to why North America cannot go to area code +
eight-digit addressing. Theoretically, you're increasing the number
availability by ten but don't have to create a new area code.

Aussie's done it, so have Brazil, Japan, France...

If planned for early enough, it could have been done if use of 0 or 1 as
the second digit was for longer line numbers. But you're misunderstanding
the situation that leads to the opening of new area codes, which is not
now, and never has been, about rapid exhaustion of line numbers.

Area codes have ranges reserved for expansion, but quite frankly, it
should never come to that.