Well, maybe not that drastic, but things have changed. In my description of this blog, I mention the statement I once read that claimed that scientific knowledge doubles every five years, but medical knowledge doubles every three years. Some have looked at me askance...whatever "askance" is...and said, "Well, bright boy, if that were the case, wouldn't they have cured all diseases already? And wouldn't the swine flu have been shot down the first week? Oh, and wouldn't we have regular spaceships to the moon if we doubled our scientific knowledge even every five years?"
What we have to keep in mind is just how ignorant we are. Not so long ago, we were bleeding sick people to clean out the bad blood. And those Wright boys were just managing to skim the ground out there on Kitty Hawk.
Knowledge could double a whole bunch of times before we make a dent in our ignorance.