It's simple, when I think of progressive metal, I think of Dream Theater and bands in that vein. When I think of power metal, I think of bands like Helloween, Blind Guardian, Rhapsody, etc... You can't be seriously asking me why those bands do not fit this genre. I think it is quite obvious. This is Prog/Power; it can't be any more explicit than that. Thrash, Death, Goth, Hardcore, Punk, etc.. shit is known as the Jack Koshick ShitFest. I'm sure no one says to themselves, wow, there is a prog power festival; I wonder if Devin Townsend or Mercenary is playing.
If you want to try and make the argument that these bands do fit, then all you are doing is trying to strecth the meaning of power, progressive metal. For that matter, you can feasibly try and group any type of music or band into the progressive, power metal category. When I hear cookie monster vocals, and growling, I'm sorry, but I'm turned off, and last time I checked, that was categorized as death metal. I don't care how techinical it is and how many time signature changes there are, and how melodic it is, etc... It is death metal, and this is not prog death 4.0, it is prog power 4.0.