This thread is still going? Interesting
When was Asterix first published in the United States? If it wasn't easily accessible pre-internet nobody's gonna be able to read it in the US. I haven't heard of it being published in Gold Key or Charlton (which would have probably been the most likely place it would have been published)
Outside of the comics itself, were there cartoons that could have introduced the characters to American audiences? Even TinTin had some of his cartoons aired in the US, obviously Smurfs and Snorks had very successful cartoons in the 80s