There is an extensive literature analyzing current economic theory and practice. No one believes that economic theory is reliable. Some people, those that rely on the theory for a living, make excuses and carry on.
The current Economic System and Financial System supports things the way they are and the many many people and institutions that profit from the status quo structures. They will not allow significant change as long as they have the upper hand.
The question becomes, where do they not have the upper hand? Where is there enough freedom of choice to experiment with different styles of economics?
Perhaps it will be helpful to make a simple drawing of the essentials of any economic system--just enough to begin having a conversation where we can know we are talking about the same things.
Here is one sketch, quite incomplete: Local Economy.