The $10B launch loop was looking at $300/kg but Starship will likely beat that. The $30B launch loop is looking at $3/kg which - yeah, that's pretty good, but if every country is doing their own Starship, I'm unsure anyone will bother. You need a lot of land for that, preferably equatorial.
Space tower isn't fucking happening and you are on drugs to be considering the dyson sphere with a straight face. Space city is another ain't-gonna-happen; just build the colony on the moon, it scales better.
I'm going with Skyhook, as the cheap version of the geosynchronous space elevator.
