Probably true although the arc should perhaps emanate from security or legitimacy (both downstream of hash rate) rather than hash rate itself. Hash rate in and if itself isn't valuable, only what it accomplishes.

Also, the paper I linked doesn't attempt to model purely speculative value, although speculation based on a future value of the network is considered. As such the paper follows the structure of the diagram as-is, somewhat (increased hoarding would occur due to increased expected adoption). "Expected" not being mentioned in the diagram is perhaps a flaw.