Matt Yglesias posts on a recent New Yorker article on the (hoped for) revitalization of AOL, specifically the idea that many people are still paying AOL even though it's not their ISP and it's perfectly possible to use the AOL mail system and the AOL interface without paying. He calls it a "scam".
Why do people do such things? The answer is, of course, there's a tremendous inertia in human affairs. Many of us don't like change. Many are lazy. Many procrastinate. Many value time over money. So the bottom line is we don't do the things we ought to, like changing from AOL, or backing up our hard drives, or changing our passwords every six months, or...
That's true of the government as well. Just look at the Marines. They haven't land on a beach since Inchon in 1950, but they were still buying amphibious tanks.
And it's true of private enterprise as well. Just look at GM in the 70's, the 80's, the 90's. Then it went bankrupt.