I didn't realize that, thanks! After looking at Wikipedia for a bit it seems there are two phases under the PCT, an international phase that is sort of like the main part of a patent application, and then the national phase that actually creates the patents in each region/nation based on the first phase. The first phase is like what I had in mind: You file once in one country but the results of this filing apply everywhere.
So as I understand it you don't have to do the full process everywhere, but you have to actively register everywhere where you want protections. And there is no automatism to the second step(?)