solar system - Is it odd that our Sun has so many planets?

From an exoplanet-finding point of view, the Sun has between one and three planets.

The major exoplanet-finding techniques in current use involve watching for either periodic Doppler shifts as the planet's gravitational pull causes the star to wobble, or periodic brightness shifts as the planet transits the star. Both require that the planet is large enough and close enough to generate a measurable signal and that the orbital period is short enough to let astronomers distinguish periodic variations from one-off variations; the transit method additionally requires that the planet's orbit crosses the star from the point of view of Earth (which favors close-in orbits). Looking at the Solar System with these techniques:

1. Mercury: too small


2. Venus: Maybe visible


3. Earth: Maybe visible


4. Mars: too small


5. Jupiter: Highly visible


6. Saturn: Orbital period too long


7. Uranus: Orbital period too long


8. Neptune: Orbital period too long


9. "Planet 9": Orbital period too long

If you look at this graph of exoplanet discoveries, Jupiter is solidly in the cluster of blue Doppler discoveries, Saturn is just past the "we've been watching for one full orbit" right-hand edge of that cluster, Earth and Venus are somewhat below the sloped minimum-period-mass line, and everything else is nowhere near the detection range.

The reason the Sun has far more known planets than any other star is simply because we've got a better look at it.