not all bands of course (Stratovarius my beloved), and other subgenres can be guilty of this too, but not this much. much of black metal is very same-y but the biggest names like Darkthrone and Mayhem actually keep reinventing themselves quite often
I especially keep pondering this after last month, when my friend saw Kamelot live (because of a different band, so he had no idea how they sound) and he said that they were pretty capable, but it felt like they played the same song over and over
