Once a site has become a Google authority site (with some site links showing under it's listing) can it be defeated from that top spot? If so how?
Yeah sure it can, i've beat a site with sitelinks. First it dropped the sitelinks and went back to a double listing in spots 1 & 2 for a few weeks then i moved in to #2 and a few days later #1. Funny thing is i havn't got sitelinks for the term yet.
Yes, sure it can. Just build up your backlinks, try to get authoritve links and watch the competition flourish. You'll beat them in due time.