Your opinion might be remotely valid if from the perspective of a listener of more evolved metal that followed the proginating class of bands you just denounced
My cd collection is an even mix of speed/thrash, death, black and heavy. I listen to all kinds of metal and have all the death metal albums you mentioned.
Personally, I find nothing special about Obituary, Amorphis, Deicide or Morbid Angel`s early work either, and would say that Floridian death metal, with a few exceptions, bores me to tears. I can appreciate the musical skill of say, Morbid Angel but find them to be shitty songwriters, much like Deicide and Obituary. I will conceed that Legion, Blessed Are The Sick and Cause Of Death are probably the best respective works by those bands but nothing I would call great, or even very good.
If Bonded By Blood, Pleasure To Kill and Darkness Descends represent the best of speed/thrash metal then I`m Orlando Bloom. I could mention AT LEAST 30 superior releases from that genre and era without blinking an eye.
I`ll refer you to my earliest post in this thread for recommended bands as your knowledge on the subject appears to be severely limited to the most obvious groups.