It happens because once in a while these self-proclaimed seers match a correct result through their predictions, and once it happens, several media channels start sharing these news, giving legitimacy to the seer's predictions. And since a lot of people in our socities are guided by what the media tells them, immediately these people go to the seer asking for advice and blessings.

However, since the correct result was predicted by coincidence, and not by theoretical supernatural skills, the seer starts giving incorrect predictions to the people who go after him. Then slowly, all the hype cool down and we don't hear about the seer anymore on the media, unless he matches another result once again. Then it's possible the hype restarts and more people go after him for the same purposes.

That is how these seers and the media make money, while the fools following them lose everything...