I don’t think elite is the game for this. Perhaps you can try firing up Stellaris once you reach 5bil.I was watching a videoclip about eveonline particularly the emphasis on PvP and I was suddenly inspired by a potentially MASSIVE change to Elite Dangerous:
Once a player hits 5 billion credits (or whatever) the game invites them to create their own empire. If the player agrees, the game transports them to a seperate unchartered part of the universe where the player can start building an empire using a mixture of NPCs and player invites. Game gives the player a time limit (maybe 1 month) during which time they buildup their empire using NPC and human players, understand the rival (player) empires and develop defense and attack assets. After the time limit expires, the player's empire is fully exposed to attacks from rival human-created empires, basically PvP empire wars.
I think this change, whilst massive will change the entire dynamics of the game and give it much needed longevity