Your comparison is of no merit. And also, there are 1 billion Catholics, approx 500 million EOC in the world today..add to that the Coptic Church, and the Anglicans, not to mention a few Protestant denoms here and there that believe she was ever virgin...so that brings the number of those who believe she was EV, alive today, at over 1 billion. Now go back for 2000 years, would you not say that there have been billions who believed she was EV?
Now onto your comparision, because I was just waiting for someone to say this..you brought up muslims. Now if the majority of the world were Muslim (which it is not), then them being in the majority would not neccasarily make them right. Why? Because this is just a belief in something, they are not interpreting something. With the belief that Mary was EV, this belief comes from interpretation of Scripture, not just of a belief of it. So therefore, when it comes to interpreting something, majority would be right. When it comes to just believing something, majority may not be right. Not to mention the fact, that alot of the billions who believed she was, are people who were Greek, and can interpret the original text. You also have in that billions, those who came directly after the Apostles, and/or were taught directly by them..
And like it has been said 1000 times before adelphoi does not imply they were blood brother's, and Scripture NEVER says she had any other children..so you and the other's, are trying to get it to say what YOU want it to say...going against 2000 years of teaching and interpretation..