As pointed out, there is likely also a correlation between amount of addresses and velocity. Or rather between the slope of amount of addresses and velocity.
More addresses being used and created indicates more different people use it (adoption) and that the same existing people use it more frequently (adoption + velocity).
The increase in velocity, however, would probably work against the increase in price caused by increased adoption.
It would be interesting to find a way to differentiate between these two powers affecting the price.