It's worth noting that the vi input models survival is in part due it's adoption in the POSIX standard, so investing time in learning would mean your guarenteed to be able to work on any system complying to these standards. So, like English, theres power in ubiquity.
As far as alternatives go, I doubt an alternate model editor would survive a 30 day free trial period, so its the same reason more people drive automatics than fly jets.
