It's all part of the HUGE rethink needed re: asymmetrical warfare.
I don't doubt it will be true someday, but I will bet money it will not be 6-10 years before manned aircraft are obsolete.
I believe the statement you make is the equivalent of saying that Battleships were obsolete in WWI. They were not. Although, with air power starting to become a factor, someone could see that was going to happen. Someone like Billy Mitchell.
All technology eventually becomes obsolete, and there is nowhere that is truer than in warfare. Nobody disagrees about that. Everyone disagrees about when to drop one technology for another.
It is like that old joke about the guy who asks a woman if she would have sex with him for money...when she asks how much, he offers $20 and she, outraged says "What kind of woman do you think I am?" and he replies "We have already established that...we were just negotiating prices...:)"