I'm not sure the author is taking into account observation time and the orbit diameter of planets. In other words, it could just be that planets in similar orb

I'm not sure the author is taking into account observation time and the orbit diameter of planets. In other words, it could just be that planets in similar orbits have similar sizes, which would be roughly consistent with our own Solar System. Jupiter alone takes almost 12 Earth years to get around the Sun. It seems to me that an observer on a remote planet on the same plane as our own Solar System, observing us, would likely only see the inner 4 planets (if anything at all) during a 4 year observation window similar to Kepler.