First, rooting and locked ROM's aren't the same thing. You can root many locked phones. See the Droid X for example.
Second, the facts seem pretty clear. The Thunderbolt has locked ROM's and then some. However, they've been unlocked though the process is NOT simple to do so. I jump through enough hoops already just maintaining an alternative ROM setup. I don't need a phone adding more to the equation. Thanks, but no thanks. If the phone were flawless outside this, hey, maybe. But it's not so I'm no longer interested. The Bionic seems like the right solution for the patient users out there.