First, Game Theory is from Mathematics, not Economics.

Next, Policy Making is Politics, not Economics. Sure, many Economists end up working in it, but I wouldn't actually blame Economics for all the Conclusion-Driven Model Crafting that goes on in there - that abuse of Mathematics and modelling to overwhelm and swindle "people who aren't good at maths" is a perversion of even Economics.

As for the rest, the lack of reliability of central bank forecasts of thing such as GDP Growth and Inflation would indicate that whatever they used to base their forecasts on isn't reliable enough for publishing.

As the saying goes, Economists have predicted 8 of the last 2 Recessions.

Back in the day when I worked in Finance and followed those things, it was quite extraordinary just how much of that was flipped around and re-explained when the final numbers came out and things turned out to be very different from earlier forecasts.

More in general a lot, if not most, of Macroeconomics does not seem to be Falsifiable: whenever the mathematical models created based on the various theories in Macroeconomics fail to predict what happens (often by a huge distance) it's invariably blamed on "unexpected factors" - if "unexpected factors" are making your models fail by a huge distance you don't really have a theory that explains reality and are really just practicing what's at best semi-guided guessing, same as how in the old days people predicted the weather for the next day by the color of the sunset and how much the bones of old sailors were hurting.