It says in the article.

The reason given is rising raw materials costs, i.e. metals, and the price increases they’re talking about are on the order of around 10% which is obviously a slap in the face along with everything else that’s going on in the hardware world, but by the same token pretty minimal compared to said selfsame everything else.

I think I paid $40 for my CPU cooler. So, if I ever need to buy a another one for some reason and now it’s $44, well, I guess I’ll live.