Dragonforce are only a good example at the most shallow, face value. They don't believe in the message; if it isn't clear from the music, read an interview with them. They are admittedly tongue-in-cheek in the most "ironic" possible way. Also, they fake it on their instruments and incorporate gamer influence into their music. Good or bad regardless, they are power metal deviants and not a good example.
Yeah, sorry Cargest but Dragonforce is just ironic hipster cockwaggery.
incorporate gamer influence
fucking kids and their games
Completely irrelevant, everyone knows metal of all stripes (yes, even death and black metal) owe a debt to DnD and fantasy pulp lit, which are now manifested in videogames. And Trey Azagthoth gave hails to Nintendo and Castlevania in the liner notes of either Blessed or Covenant, so the influence of games is hardly a bad thing and, I might add, it's entirely to be expected. Dragonforce's main problem is, as noted, their thoroughly ironic delivery and vapid interpretation of metal's values, along with their fucking garbage songwriting.
Power Metal is just another marketing term for whats basically either Speed Metal or Heavy Metal with fantastical epic themes and typically lots of crescendos to get you totally pumped up. It's like Black Metal for kids who find it unpalatable. Powerlifting on the other hand is a lot better than Power Metal and is highly encouraged.
I think you're right, but we can probably take your statement one step further and say that, at bottom, all genre labels are marketing terms. Power metal, Burzum, jazz, and the Hokuto no Ken soundtrack
are at the molecular level hardly distinguishable. We differentiate between them, however, because not all vibrations are pleasing to all people and we need a way to communicate this (i.e., marketing). That said, power metal is a fucking gay phrase, and I'm tempted to shun the genre on the basis of the name alone.
short version: let's stop thinking that genres are rigidly defined on the metaphysical plane, they're at base useful marketing devices