The reason it’s only 5k is because once you get that far, you’ve grasped the concept of the game well enough to play it for much, much longer — to a point where it’d be boring. If I made the challenge 50k instead of 5k, it honestly wouldn’t be that much harder. It would just take longer.
i like where it is. i used to curse about getting 4000 for the challenge but after i played for a bit i got 14000 easy. also before when i played i thought the game was boreing. but i found that once you get into the game it gets a bunch more fun.