Chances(主语) are(谓语) we would perish earlier even with optimal care and feeding(省略了连接词that的表语从句).
再来分析这个表语从句：we(主) would perish(谓) earlier(谓语状语) even(后面介词短语的状语) with optimal care and feeding(介词短语作状语)
英语高手帮忙找找主谓宾,定状补Chances are we would perish earlier even with