I had a nice story about what happened to Earth, back in the days when I was thinking about making a campaign.
After the isolation most of the Terran heavy industry was gone, and military was weak. Pirates and other criminal groups infested the system. But several smaller corporation saw their chance, bought all know-how they could get, and quickly grew in size. They equiped the newly founded Provisoric Terran Republic with ships and weapons to fight the pirates. After this threat had been eliminated all Terran resources were used for scientific research, to find a way to re-open the node. So a lot of new inventions were made that helped Earth to regain wealth.
Not knowing what happened to the Terrans outside Sol the Terran Defence Destroyer Majestic was constructed, 4.5km long and equiped with the only known weapon that might penetrate the shields of a Lucy, the mighty Impulse Wave Cannon.
With the time a new threat arose: a group of radicals that claimed that Sol was only strong because it was isolated, and that tried to stop all effords of re-opening the node.