I've always assumed that committed conspiracy theorists are just trolls rolling with it (because nobody could be so stupid as to actually believe in the conspiracy's premise). So no amount of evidence is going to "convince" them, because they already know the truth, and don't care.

But then perhaps over time, they somehow attracted people who genuinely are that stupid, and uncritically believe? That demographic is obviously going to be too stupid to critically assess any new evidence either.