However, I still find it odd that the original intents of kata were not preserved even in Okinawa, as reeskm is claiming. I understand how they may have been no longer taught by Itosu, but he was only one of many To-De experts on Okinawa at that time. How was this knowledge not preserved through other masters? Or did they all follow in Itosu's footsteps?
The prevailing theory or hypothesis that I've come across is that any good master keeps his best techniques to himself out of a self preservation point of view. The would never teach their best techniques to their general students, and would reveal their secret techniques to only their best students they considered trustworthy enough to pass on their greatest teachings. The theory goes that some would rather die than pass on knowledge that could end up being their undoing or bring them or their schools disrespect if it were to be misused.
My teacher practices this old way.
The modern way is to put it all out there - to reveal it all either out of the interest of preserving traditional MA, for profit by selling expensives videos or books, or because of generosity and that technology make it possible for the betterment of all MA worldwide.