> CDU has been trying to adopt more AfD positions

> this keeps only strengthening the AfD

I am unfamiliar with the details of German politics but if what you say is true, I am not surprised at all. I do not think that one can "win" against those parties by using their methods or adopting their positions. Because they are genuine at it. While the others would only fake it.

If the voters have a choice between a fake populist and a genuine populist, they would, in my opinion, naturally pick the genuine one.

I think that one of the reasons is that the "fakeness" is not very appealing to anyone. So they prefer the "real deal".