Arne Jacobson, Charles and Ray Eames are all dead, so they no longer collect royalties. Moreover, in the US or Canada a design patent is valid only 20 years (max). All of these ideas are now in the public domain and can be made and sold by anyone. I think it’s wonderful that these great designs are now widely available.
Having said that, I wouldn’t order anything online. I want to feel the material and flip things over to make sure the piece is built properly. If it has a reputable factory behind it, I would be more tempted.
Having said that, I have almost only Ikea furniture and my Herman-Miller office chair.