I find it odd that people here are so encouraging on this topic, if this was asked in Unity forums the responses would be “you are wasting your time because you have a 1% chance that your game would succeed”
But then again I decided to make a FPS game similar to half life. I think this is a much more realistic goal
Usually when you see those “my game didn’t make any money” or “my game was a flop” thread on Unity and you actually looked at the game, they are always mobile type games that not even the developer would play cause the quality is so bad and is not interesting
I think for a game to succeed, besides marketing offcourse is that the game actually has to have some quality put into it, and also it has to be interesting and fun. If it isn’t a game you would care to play then I think it should be no surprise that nobody bought it.