( )has been said above ,grammar is a set of dead rules.

因为这是个定语从句,as的用法在此相当于which,也就是说He was beaten in the game,which has been expected。他在游戏中以失败告终,这是预料中的事,答案中的as就相当于whichWhat一般都是用于宾语从句的,例如：I don't know what you are talking about。我不明白你在说什么,what you are talking about构成了一个宾语,在句中形成了一个宾语从句。如果你要用what来转换上面那句子的话,可以这么说：He was beaten in the game,and it was what has been expected。或者What has been expected was that he was beaten in the game。