I know that- what most of us are saying is that not all but a lot of newer mainstream american metal bands from the past 10 or so years tend to write simpler and more predictable song structures that sell well in the US as it's easy to get into.
That allows them to headline tours- so a lot of bands from other countries start out as opening acts, want to be more popular over there, and so they change their sound ("American-ising" it for lack of a better word) to fit in better & hopefully gain new fans with the bands they're opening for; often losing most of their original style.
No one's having a go at you specifically sir as you clearly like decent music & there are a bunch of people in America that do- I just find it happens to a few metal bands that drastically change their sound when they tour in the US & then go to record a new album.