If you ask the question in the light of "how many people use this, compared to active Gmail users?" (11,616 vs ~ 200 million [1] = .006%), and then ask "how much is it worth to block this?" (probably a very small number), I personally come up with "a very very long time, if ever" for your "how long until..." question.

[1]: http://www.quora.com/Gmail/How-many-total-active-Gmail-users...