Rooting isn't impossible on the Droid X, it's just annoyingly difficult. If someone wanted to distribute malware ROM images, they just need to wait for the root to be accomplished by someone else. There's no real protection.

If it's Verizon that's behind this to "protect the network" it's starting to sound like we're heading for another "Carterfone Decision":

https://secure.wikimedia.org/wikipedia/en/wiki/Modem#The_Car...

The Nokia N900 doesn't make life difficult for users. To root it you just download and run 'rootsh'. Done. The network hasn't exploded simply because it's easy to root and update ROMs.