"And what the matter how many churches agree?"
There in one sentence you just covered all of the problems with ECUSA and all over the left wing of the theological spectrum (Protestantism). God did not found churches (plural). He founded a church (singular).
Rev 2 & 3: "Hear what the Spirit says to the Churches..."
"Christ loved the Church and gave Himself for her."
It's used BOTH ways in the bible.