And for the record, we have in this thread provided a list of a number of traditions which were not incorporated into Scripture yet abide still. Moreover, we have demonstrated through extensive quotation from the Early Church Fathers that these traditions are indeed ancient, from the earliest days of the Church in fact.
These traditions include:
- Trinitarian doctrine;
- The Nicene Creed;
- The liturgy
It doesn’t stop there, of course. The sacraments of the Church themselves are a type of unwritten tradition.
Protestants today are embracing the monastic tradition long practiced by Catholic and Orthodox and stemming from the very early practice of St Anthony and others.
Did I mention saints? Many Protestants accept the Catholic list of the saints, taking for granted that the Catholic Church is able to discern who is in heaven and who is not, at least among the martyrs and other august personages.
Speaking of these personages, Protestants also accept the Catholic definition of who among the Church fathers is considered to be orthodox and who is considered to be a heretic—up to 1520 at least (their fondness for Wycliffe and Tynsdale notwithstanding). Note how few Protestants stand up to boldly proclaim the theological virtues of Arius or Nestor or Marcion. You’d think that “Here I stand; I can do no other” would apply to them as well, were Protestants consistent regarding sola scriptura.
So yet another answer to why everyone isn’t Catholic is, “Everyone is—they are simply cafeteria Catholics who practice theology by subtraction to suit The Atomic Church of Me.”