So I will not see any passengers at any default airports?, correct?
You won't see passengers, but they are there, it's just the default replacement jetways is opaque, because it's designed to look as the original one, just much better.
[ even though I can see through the jetway, and the pax bus never shows up? is all that by default?.
No, of course. If GSX Level 2 is activated (and GSX too, of course), passenger will surely show on default airports if you place a transparent jetway there, and they will show on all parkings with a bus and stairs.
I assume your airplane is correctly configured for GSX, with all doors in the proper position.