um. the majority of networth is in military. military requires upkeep.
http://www.earthempires.com/ffa/26/ranks
the winning country last set had $1,129,573,936 networth. His expenses on that networth are $1.5b cash/turn. $1.5B cash is about 6m NW for a 0mb theo. If he ran a day of turns with that kind of networth he would lose $450m+ NW in expenses.
On tag servers we store our networth in bushels and sit those bushels on the market at non saleable prices. As the end of the reset approaches on tag servers the players all change governments, sell their bushels, then buy military.
So the winner in alliance last reset went from 20m NW to 300+m NW in a week.
The best players generally play alliance. I often consider FFA and Express chump servers. Tourney has an active player base that can be counted on my fingers and toes. Primary is competitive, but there you will find 40-60 players capable of finishing t10 whereas in alliance there are probably 150-200. If you would like to learn the strategies and math behind the game you can find the best at
http://www.lafamiglia.org
I'm considered a lazy-can't finish-blase netter in LaF but I still have spreadsheets that can calculate most of what I do. I think the destocking spreadsheet has around 40 variables.