I started out making games for fun that nobody would see. I just used Construct 2 Free Edition and because I didn't want to pay $200, I only did it for fun and never put anything anywhere (not that I ever finished anything.)
Then, I looked and saw Scirra Arcade, then saw the free edition's 100 event limit, and that forced me to make smaller games. But hey, I finished them faster and now there are people across the world playing my C2 games.
Then after thinking about it, I had this idea to start making a game franchise with Construct Classic. Why Classic? It's all free, so I can publish it anywhere free of charge from Construct anyways... To put my game(s) on Steam I have to pay $100... per game. Although selling my game(s) for $5 a copy, I would only need to sell 20 copies to get my money back. And there have been more than 60 plays on my first C2 game on Scirra Arcade, The Big Apple.
So it is certainly possible to start out as a private just-for-fun game developer and then become a public let's-make-money game developer.