Music in general has become worse than what it was in the 90s and 00s and I'm sure this is the case for metal music too. I have listen to most of the bands you mentioned, Blind Guardian is my favorite and the album The Dark Ride from Helloween has great songs that I have listen to a lot
You are right about the blues influence in the American music, I have noticed it too, I tend to listen more European bands than American but I also like collaborations from both sides of the Atlantic like Demons and Wizards