> probably much easier to jam

Definitely much easier to jam. Much higher orbits for gnss satellites, much lower signal intensity.

Also, starlink uses phased arrays with beamforming, effectively creating an electronically steerable directional antenna. It is harder to jam two directional antennas talking to each other, as your jammers are on the sides, where the lobes of the antenna radiation pattern are smaller.

Still, we're talking about signals coming from space, so maybe it is just enough to sprinkle more jammers in an urban setting.. I'm curious as well.