I agree with you on part and I disagree with you on part.
Let me elaborate: I abhor the sight of people picking their "truth" according to their convenience. This happens a LOT. Just to give you an example, people often want God to be one way or another and then interpret the scriptures according to how they want God to be, rather than trying to figure out what God is like from the scriptures.
Now for the part where I disagree with you: The original text might not be perfect. And if someone is able to truly improve it, it should be done.
Glad we can agree on something
( maybe not to often that happen)
So to the part we disagree.
In my understanding, the original teachings ( orally most often as the beginning) are from an enlighten person, God, Buddha an so on, they have realized a truth so pure that those of us who has not realized it, can not understand it. And we can not see any flaw in their teaching.
The only time I can see your statement come true, is if an even moire enlighten being come along and give an explanation to the question about truth.
In my understanding, truth is not constant, it will look different depending of the level each person has reached. Meaning someone who have only studied a spiritual teaching for a week, will not have realized the same truth as one who has been studying the teaching for 10 years, 40 years and so on.
The more we understand the more pure the truth become. As far as I understood