One of the major problems with Anti-Zionism as a position is it is devoid of coherent ideology. Anti-Zionism basically represents an amalgam of different beliefs and views all United by their opposition to Zionism. Much like anti-communism can contain people with a variety of views ranging from absolute monarchists to to social democrats to liberal republicans, Anti-Zionism also contains this range of differing and sometimes opposing ideologies (Islamic theocrats, Palestinians Nationalists, International Leftists). This diversity may be good in that it helps create a large diverse coalition of groups which can help lend legitimacy to its goals. However this also leaves Anti-Zionism devoid of ideology and unable to concretely appeal to Zionists enough to convince them to abandon Zionism. The ultimate goal of Anti-Zionism is to convince Jews that Zionism won't work. Discounting the genocidal forms of Anti-Zionism, all anti-zionists seek to eventually end the Jewish state in some way, most through eventual dissuasion of Jews to Zionism. This is, in my opinion, the key area of failure for anti-zionists.

Anti-zionists have failed to properly articulate an ideological solution to Zionism or more specifically they have failed to answer the Jewish question. Anti-zionists have failed to solve the original cause of Zionism. Bundism originally provided Jews with the ideological alternative to Zionism, however most bundists died in the gas chambers, essentially proving the Zionist argument.

There is one more alternative to Zionism which is Haredism, essentially the embrace of traditionalism and simply to await the Messiah. But to increasingly secular Jews Haredism could not provide the answer, it's failure having been the previous 2000 years of history. The holocaust also somewhat dampened Haredism as an alternative (how could God allow this?).

This is all to say that modern anti-zionists have failed to respond to Jews with a coherent alternative, which specifically answers the Jewish question. The type of ideology which they wish to create might be termed Diasporism, essentially this would hold that the Diaspora is the key to Jewish culture and survival, as opposed to Zionism which hold that holds that Zion (the land of Israel) is the key to culture and survival. I have yet to hear a single argument from anti-zionists about the benefits of diaspora, or why diaspora is better than consolidation in Zion. Until anti-Zionists are able to create a coherent ideological alternative to Zionism, such as Diasporism, they will never be able to convince Zionists to abandon Zionism.