That said, it would be quite exciting to see all those launches, and the end goal is a worthy one.
But wait, you don't actually need to restrict yourself to one spherical surface. You can place your 30k sattelites anywhere in a Earth's-surface-sized spherical shell that's 400 miles thick. You could literally put those 30k sattelites in a single straight line above some point on the earth, and still have 350 miles of shell thickness left.
Congestion on low Earth orbits is really a non issue, especially if the satellites are designed to deorbit after their useful lifetime.
Lets pick your assumption apart - there are 200 million motorcycles in the world, but there are only an esitmated 35 million km of roads. That means there are approximately 175 meters of road per motorcycle. That seems pretty reasonable, even if they were all on the road at the same time. But they aren't alone - there are also approximately a billion vehicles. That takes it down to about 35 meters per vehicle. Thats without factoring in the loss in space for intersections, the drop in capacity at each of those intersections, or addressing the fact that most of those vehicles are clustered in high density urban areas.
Now we are lucky that not all of those vehicles are on all of those roads at the same time, because they can be removed and parked.
It is certainly possible to overlay orbits at different altitudes, but then you have to manage spectrum congestion, because those 30k satellites in a straight line above some point on the earth are useless unless they can actually communicate with ground stations.
Not all orbital slots are created equal either - some have better coverage of human habitable areas than others.
Oh, and there is the small matter that each time one of those 30k satellite degrades, it becomes between two and hundreds of thousands of devastating fast moving particles that can destroy other satellites (don't believe me? look up the number of windows that have been destroyed by paint flecks in orbit).
Don't take my word for it, read up on NASA's articles and quarterly publications on orbital congestion.
Reminds me of "beer: the cause of and solution to all of life's problems!"
[0]: https://orbitaldebris.jsc.nasa.gov/ [1]: https://spacenews.com/esa-spacecraft-dodges-potential-collis...