Why don't AM radio stations come in clear? What is the point of having them?

The clarity of an AM station depends on many things, including atmospheric conditions. Depending on where you are, they can be very clear. FM is better for things like music, but if what you're producing is along the lines of news or talk radio, then with AM the quality difference won't matter and you can literally, if the conditions are right, send your signal halfway across the world.Why don't AM radio stations come in clear? What is the point of having them?
They can get further away.

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