Using a measurable quantity N as proxy for singularity progress and or status is valid, Vinge himself did it in a long now talk (power generation per person iirc). So in some sense asset accumulation per entity or organization could be a similar measure. Not saying this author does a particularly good job of it, or that it's a good measure however.

http://longnow.org/seminars/02007/feb/15/what-if-the-singula...