At any given point in time we make use of "new" and "old" technology, as well as anytime in between. Most plumbing technology is millenia old yet works quite well. The Boeing 747 is "old" technology in commercial aviation yet it has a superb safety record. Due primarily to cost constraints, we never employ the "newest" technologies all at once. But this may in fact be wise, as most "new" technology is not quite proven.