Of course it's always being considered, but the question is how much effect it has in practice. I guess this depends on your ontological categories, but personally I distinguish between "Bing is copying (if you want to call it that, and fair enough) certain Google results" and "Bing is a copy of Google" (which I think has been alleged or insinuated, but not shown). The difference is a matter of quantity turning into quality.

I think they probably have statistics that convince them of the latter, and they should show them, so we can see if people outside Google also find them convincing.