I get that its telling you that you can use the different means to purchase more area, however what happens when you have all three ways locked up?
The three means are:
Victory: using medals (will show how many currently in game expansions in inventory, be they affordable to you or not)
Diamond: You are allowed to use 2 diamond expansions per era (will show how many left in inventory ONLY if you have not used the max of 2/era, once you are caught up the option completely disappears until you advance)
Reward: Tech tree and Campaign map. (Will only show in inventory if they have been unlocked on CMap/tech tree. Will not show you any coming up later ONLY unlocked and available to use right then and there)
Available expansions will show available medal expansions only. To see any remaining tech expansions yet to be researched look ahead on your tech tree. For Cmap you can use the wiki to view future CMaps and see how many more expansions are coming your way.
according to the new system i only have 6 more expansion spaces and then i'm done but i will still have a lot of area unused.
The current land marked off as possible of being expanded currently excedes the amount of available expansions to anybody. This was done for future growth of cities as more expansions get added into the game with every new era, or in this case, addition of OF. The new medal expansion will be available to all players who are able to gather that many medals. The new diamond expansion will only be available to OF players as there is a strict limit of 2 diamond expansions per era and you are not able to use a later eras diamond expansion without moving into that era.
it seems that the players who have been around for awhile got/took the chance to buy diamonds and expand definitely have the advantage. any info on how this works?
On the contrary, older players were actually at a strict disadvantage in terms of space. With medal expansions available to all independent of era I am able to use medal expansions that were released when the Future Era or beyond was released. When older players were in my era if that era was the current era there were no further expansions to be had.
Lower era cities now have the possibility of being much larger due to medal expansions that were released later on.