What could your point possibly be here? Do you honestly think that by taking a swipe at Scripture (implied by your comments) you are going to enhance the authority of "Tradition".
"In any event, the Church was already developing oral traditions long before St. Paul wrote "
All the "Tradition" you need is contained in the Scriptures.
Luke 1
"Inasmuch as many have undertaken to compile a narrative of the things that have been accomplished among us, just as those who from the beginning were eyewitnesses and ministers of the word have delivered them to us, it seemed good to me also, having followed all things closely for some time past, to write an orderly account for you, most excellent Theophilus, that you may have certainty concerning the things you have been taught."
"How does Protestantism, arriving on the scene 3/4 of the way from Christ to the present day, justify the disavowal of tradition or the continuous teaching office of the Church?"
Protestants did not "arrive" on the scene - we are protesting catholics! We have as much (if not more) of an organic connection to the early Church than you do.
"The argument is always made that such-and-such teaching of Catholics cannot be found in the Bible. Usually, that's not the case. But, on occasion, there is some truth to the claim. But so what?"
Here's the "so what"...
Isaiah 8:20
"To the law and to the testimony: if they speak not according to this word, it is because there is no light in them."
Revelation 22:18
For I testify unto every man that heareth the words of the prophecy of this book, If any man shall add unto these things, God shall add unto him the plagues that are written in this book:
"All the 'Tradition' you need is contained in the Scriptures."
Except for the doctrine that, "All the 'Tradition' you need is contained in the Scriptures." You Protestants invented that.