Alfred North Whitehead
Deleuze's and Latour's opinions, however, are minority ones, as Whitehead has not been recognized as particularly influential within the most dominant philosophical schools. It is impossible to say exactly why Whitehead's influence has not been more widespread, but it may be partly due to his metaphysical ideas seeming somewhat counter-intuitive (such as his assertion that matter is an abstraction), or his inclusion of theistic elements in his philosophy, or the perception of metaphysics itself as passé, or simply the sheer difficulty and density of his prose.

Q: Why do some people believe Whitehead's writings may have restricted his influence?
the sheer difficulty and density of his prose