我们并不比我们的祖先更能够在没有构想的家庭的情况下生活.意思就是我们的祖先不能在没有构想的家庭的情况下生活,而我们也好不到哪儿去.
语法上no more than 的解释同一楼,但是这个句子还有个重点在than were our ancestors 上,这儿用了倒装的形式,其实大可不必把were说出来,也可以说than our ancestor were.（our ancestora were not able to live with out...）就像he is taller than his dad也可以说成he is taller than his das is 一样.这种倒装可能在书面语中较为常见.
另外四楼的改动有一半是错的,怎么可能说is it emphasize 呢?does 还说的通,不过那还也太直译了.其实你的意思是“这句话的重点是不是在no more than上”,是吧?如果是的话,用does the emphasis of this sentence lie in the phrase-verbs?可能好一点（consist in 也一样）.