the anti collision manuevers are hard as well.
orbits are simpler at lower lattitudes where you run a trajectory, close to parallel to the equator.
This affects both commercial potential (fewer possible subscribers) and bandwidth congestion (dittos). For both you'd want fewer birds in those orbits, and orbital dynamics only strengthen the argument.
In order to cover those northern/southern extremes, more expensive high inclination orbits are required (in the US these are launched from California). They are more expensive because you’re no longer getting the rotational velocity of the earth for free in your orbital velocity.
So for a LEO constellation you want to minimize the launches to high inclinations and keep the bulk in those juicy easterly ones.
There are two clearly demarcations both north and south