One reason is that Firefox OS uses the Android kernel. This means that Mozilla doesn't have to beg device manufacturers for hardware support. If a device runs A

One reason is that Firefox OS uses the Android kernel. This means that Mozilla doesn't have to beg device manufacturers for hardware support. If a device runs Android, it should be able to run Firefox OS with little software modification. Another reason is that Firefox OS uses Gecko as the UI. So the two major components, the kernel and userland are taken care of; there is no benefit from forking WebOS.