There are plenty of root access apps in the Market.
As pointed out earlier, Motorola has not built a device that developers were unable to ROM. Koush developed a bootstrap application that allowed some circumvention of Motorola's attempts to stop this and allowed custom recoveries and ROMs to be installed on devices like the Droid X and Droid 2.
The locked bootloader prevents installing a kernel that is not Motorola signed. The signature is protected by, as I understand it, a very over-the-top level of encryption. Without the ability to load a custom kernel, the core of the operating system, a ROM is somewhat limited. CyanogenMod is one of the most popular and widely available ROMs. Since it is built with a custom kernel, it cannot be ported to a Droid X or Droid 2 or Droid Pro in it's current state.
Motorola hinted at perhaps looking into building future devices that were more "open" and developer friendly. I have yet to see any news about the lockdown status of the Atrix or Bionic. Even without the TI OMAP chipset security measures, it may be possible for Motorola to lock the bootloader on their new Nvidia Tegra 2 chipset devices.
EDIT: The closest thing I found to an official statement from Motorola can be found in the comments of this Moto video on YouTube.
http://www.youtube.com/watch?v=D4gpOQDcn7c&feature=youtu.be