Fear of switching
So, there's no version of Word optimized for the new MacBook. In fact, my copy keeps crashing my crash-proof machine. I just switched to Nisus. Let's see, it's faster, cheaper, compatible, more reliable, optimized and friendly. And yet, almost no one with a MacBook has switched.
The other day, my family saw the supersized version of Scrabble, which comes with a bigger board and more tiles. We played once. We hated it.
Just because something is newer or better or bigger doesn't mean you should switch. In fact, one of the big fears people bring to the table is investing the time to figure out if it's worth it (the other fear is that switching will just wreck everything.)
Getting someone to switch to super-sized Scrabble is hard. Getting them to switch word processors is almost impossible. Fear is a huge barrier, no matter what you're selling.