When I've looked at it previously, it did look like the daily author numbers followed the Steem price (or potentially the crypto market rises in general) rather than SBD. However it is quite possible that this will have changed as awareness of SBD has changed over the last month or so.

Worth noting that the same study showed that 80% of authors posting on a particular day earn $4 of author payout or less (prior to currency conversion to include full SBD value) even after the rise in Steem price. Steem is mainly populated by people earning very little, for whom the extra SBD value is likely to be significant.