They certainly can. They're competing with dirt, because you can dig up dirt and use it as filler in construction. So either they need to have some favourable p

They certainly can. They're competing with dirt, because you can dig up dirt and use it as filler in construction. So either they need to have some favourable properties compared to dirt, or the "crushing/grinding" process has to be really cheap, or the alternatives for disposing of the blades have to be expensive. If dirt was scarce, we'd find an economic way to recycle turbine blades. We should be happy to have so much dirt, not sad that we can't reuse our end-of-life turbine blades. The same goes for the other suggestion mentioned in the article, of using them to put roofs on homeless shelters - there are other materials which are cheaper and more suitable, and no homeless shelters are going unbuilt because evil energy companies won't donate their old blades.