@Steve: you're going to look too hard into the underground scene of that country, I've never heard of 80% of those bands you stated even though I've known Behemoth, Vader, Decapitated for some years now... I don't know about the American underground metal scene so I won't judge the whole scene over there. (By the way, Poland is considered Eastern Europe
, and one of the most productive country for quality death/black metal)
I think that internet has helped a lot in promoting bands over the world, which is a good thing. But the bad reaction to that is people thinking that only the good stuff comes from far away, internet giving the illusion that distances don't exist. So it's rather a pity when people keep saying "I want In Flames to tour the USA/Australia/Indonesia/Antartica/Urduland" etc... Just an example.
What I don't understand is why american bands wouldn't export themselves in Europe more easily? I live near Paris so it's ok if I want to see Deicide or Testament (less often) but those who live in smaller cities almost never have big concerts and it's not easy for most of european metalheads to see their favorite bands. That's why we euro's have our own big underground scene: because our favorite american bands won't come to our town