The hub is not in geocychronous orbit. It moves at over 6 km/sec with respect to the ground. But it does cartwheels - it rolls forward in the direction of travel, rotating once every 66 minutes. As such if a tether 4000 km long is attached, the its tip speed will be 6 km/sec in the opposite direction. So it can dip into the atmosphere periodically with no relative velocity.

There would be a rendezvous opportunity 22 times daily, and it will occur all over the world. Every country will have a chance to take part in the construction effort, since they will have a chance to rendezvous inside their own airspace on a regular basis.

So the effort here will be political as well. Not until we have world peace & prosperity will it be possible to utilize the space elevator to its full potential. Otherwise we will not be able to launch anything half the time, because the rendezvous point will be in hostile territory.