The Verge caught my attention this morning with this piece asking why Motorola isn’t shipping stock Android software on the new RAZR M and RAZR HD handsets. Now that Google owns Motorola, the thinking goes, isn’t it in its best interest to make handsets that are as purely Android as possible?

A Motorola executive agreed that the company wants to be “as close to the base as we can be,” but concedes that “we negotiate somewhere in the middle” with carrier partners looking to stamp their own brand and apps on their Android devices. As an example The Verge cites the RAZR HD, which features a custom skin and Verizon software and isn’t shipped with Jelly Bean, the latest version of Android.

This highlights the enormous power of Verizon Wireless, which is the largest carrier in one of the world’s most important mobile markets. But it isn’t just Verizon that can flex its muscle with Android — there are plenty of Android manufacturers around, and despite the presence of Google there’s nothing to prevent carriers from looking elsewhere for their hardware. And it’s carriers, of course, that are responsible for issuing updates to all the Android handsets that also feature — or are encumbered by — that extra software. And that’s the simplest way of explaining why Android continues to be plagued by fragmentation problems.