We live around 75 years. We have 75 summers, around 80 travels (in my personal economical condition of course). The people we will meet are relatively few, the projects we can tackle too.
Imagine you start to work at 25 years, because you are born in the lucky side of the World. You have 40 years working. If a game takes 3-5 years, you can make around 8-14 games in your life. Game for companies, that may be successful or not.
Or you can go indie, maybe solo dev, going alone and try to publish one game per year. Small game, of course. In that case you can leave 20-30 good games (the first will surely be a disaster). That can be your legacy as a game designer.