This question's sole answer Is it true, that commercial communications satellites account for the largest share of commercially used satellites? explains that:
the vast majority of the satellites in geosynchronous orbit are communications satellites.
Looking up the main use of such satellites, it seems to be mainly satellite phone calls and the like. Given the noted majority usage, I would've expected something else, like Internet relay, like how David explains the new LEO satellite constellations' purpose. Perhaps it's just old infrastructure waiting to be pushed out?
Therefore, what is the purpose of geosynchronous orbit communications satellites, and why is it the majority/primary usage in 2023?