Congrats Random! I'm sure if you had played another game year, you would have got 1 million, but at that point 1 year for 15k doesnt seem like its worth it. Next game I expect you will break 1 milion.
Believe me, I would have run this game out to 20 yrs if it had a shot of going over 1m. Unfortunately yr 7 netted me only 13k and yr8 only 5k. If thats not hitting the wall, I don't know what is
It's a common misconception that you can get any arbitrary score you want if you're just willing to extend the game the requisite number of years. That is definitely not the case. Very early in the game you are pretty much pegged to a curve that the game will follow and only something truly extraordinary can break you out of that path.
Growth in all resource allocation games tends to be exponential because your growth rate is dependent on how much "stuff" you have. Get more "stuff" and you grow faster. That is in fact the classical definition of exponential growth. You start off early in a deep resource hole but as you accumulate more planets, more mining resources and technological bonuses then growth accelerates.
Typically the game's scoring potential is pretty much fixed by the end of the second year if not earlier. You can see this when you get to the point that you can win the game and you begin checking the score at the end of each game year. The first time you do this forms your baseline. The next time you do this you get a value of how much the additional year was worth.
Say as an example that at the first score check your score was 300K and then 1 year later you check and the score is 600K so that first additional year was worth an additional 300K points. Then the year after that you check again and you'll find that year was probably worth only 150K points. Each year the additional gain from an extra year approximately halves. So you can get another 75K and another 37K and another 18K then 9K, etc. By then it becomes pretty obvious. If you haven't made a million by then are you really going to do another year for 4.5K and another for 2.2K, etc.?