What are your thoughts on the simulation theory?

I'm feeling as if these theories are slowly eating me inside. The rate at which the world is technologically advancing, it wont be long before we have enough computing power to create a simulation where the characters (the people or whatever you call them) have consciousness and self awareness. Lets take an example of GTA (Since gta seems to be a pretty good example on this topic), what if the main character really feels and believes to be alive. For us, we are controlling the character to complete the assigned missions, but if that guy has self awareness, how would he know that he's being controlled by a superior civilization? This may sound crazy to talk about and even crazier to think that we're really capable of adding self awareness to that character. But isn't that possible in, lets say 50 years, 100 years or even a thousands years. If it's really possible to do so any any point in the future, how do we know that it hasn't happened already? :/ What if everything around us is just a part of the simulation that we're living in. Pretty crazy stuff.

According to Elon Musk, there's a 1 in a billion chance that we're not living in a simulation.

What are your thoughts on this topic?