And I'd be on the opposite end of the spectrum.
I used to love me some metal! I grew up loving bands like Sepultura, Pantera, Morbid Angel, Cannibal Corpse, Testament, Napalm Death. I got to a certain point where I branched out in my musical interests (from not just listening to aggressive anymore), and I can't really get into ANY metal these days.
I would agree, that probably the technical boundaries are pushed more nowadays than maybe the things I grew up listening to on Headbangers Ball in the early 90's, but meh. Maybe I got old. Maybe metal got old. Maybe both.
As opposed to other genres though, metal never seemed to progress beyond a new variation of dropped tuning, or screamed vocals. IMO, it's all been done before.
Metal checklist:
Blast beats or no?
Dropped D or C tuning?
Screaming the verse and singing the chorus, or vice versa? Scream both?
One solo? Two solos? Dueling solos?
Just my opinion for what it's worth...