That's not quite it. If something is neither proved nor disproved (ruled out) by the Bible, we can credit ancient belief and practice of the Church. That's not exactly "enough people." It's not a numerical thing, a vote. It's history, using the ordinary rules of historic investigation, and weighing the antiquity, the authority and the credibility of the various sources of evidence. You may underestimate how conservative andwha sticklers for details the ancient churches were. Homousios vs homoiousios and so forth. If the doctrine of the Assumption had been heretical, I think the introduction of liturgical celebrations of the same would have caused rioting and schisms on three continents.
It's important that our evaluation of such sources take fully into account the profound conservatism of the local Churches (by which I mean, in the Catholic sense of the term, Dioceses) involved. And their extreme disinclination to let sister local Churches deviate by one iota from what they had received from the APostles.
Did you read the article I referenced?
(I copied it from the cache version and then zoomed it up in size, because that small print bothers my eyes. I wish I had a more legible version to offer you.)
Yeah, sticklers all right.
Revelation 2:1 These are the words of him who holds the seven stars in his right hand and walks among the seven golden lampstands. 2 I know your deeds, your hard work and your perseverance. I know that you cannot tolerate wicked people, that you have tested those who claim to be apostles but are not, and have found them false. 3 You have persevered and have endured hardships for my name, and have not grown weary. 4 Yet I hold this against you: You have forsaken the love you had at first. 5 Consider how far you have fallen! Repent and do the things you did at first. If you do not repent, I will come to you and remove your lampstand from its place
Most of the assemblies had already strayed not 60 years after Christ's ascension. And you want us to trust those who lived hundreds of years later?