Okay thank you guys.
The last posts of you were very informative.
So thanks for the extensive explanation!

I think you persuaded me to test unity. ^^
Wings3D looks interesting.
Not that complex building like Blender at all, but a simple Model designer.
I think that I can handle this.

Regarding the point with earning money.
I don't want to be a game designer as Job!
I am a IT specialist for system integration, so I don't want to work as game designer
It's just a outside activity and I want to create a game, which I can sell some day.
There is no time frame for me.
If it's done in 1 year....fine.
If it's done in 4 years....fine.
The important thing, that it CAN be finished one day.
And I talk about quite simple games, like "Slender" in comparison to huge games like Fallout/GTA and so on

So I just need Unity and a modelling design program like 3DWings?
Which one is easier to learn? Unity or Unreal engine 4?