Growth in games is fun. It gives players a heightened sense of accomplishment, and it can be used to morph game mechanics over the course of a game session.
In the abstract, growth is most fun when it is unbridled.
In practice, it is hard to maintain balance with unbridled growth. If balance is lost then the game loses much of its fun.
Unbridled growth creates a growth curve. The growth curve outlines the median rate of growth a player can progress along which will maintain a balanced challenge. If the player gets ahead of the curve the game loses its challenge. If the player falls behind the curve the game becomes more challenging to the point of impossible.
What's more, a growth curve is exponential. Riches beget more riches and debts beget more debts. If the player can get slightly ahead of the curve early on, that will grant them an edge to get even further ahead later. Conversely, falling behind a little means increasing missed opportunities later.
The rich become richer and the poor become poorer.
Most games do not have unbridled growth. Most games use one or more methods to restrict growth.
Below is a collection of restrictions games use to restrict growth