All I can say about that is, it depends. Nobody can tell you for sure. Your games will sell (or not) differently from anyone else's.

Make a game. Promote it. See what happens then. Make more games.

That's how it works for everyone. Some people get lucky, for others it remains a hobby, and nobody can promise you anything. So just try it and see.

I hope you don’t take this the wrong way, but (in my eyes) using IndieDev as a user/studio name is about as generic as naming yourself nobody in particular. Sticking with that name would make building a recognizable brand unnecessarily hard for yourself. Before you think about “average income” maybe spend some to time think about how you want to represent yourself (and your games) online. Maybe pitch some ideas to the friends who test your games for you.