That's not how it works.
Even when (for the sake of argument) more pts were spent on cruises, those pts were still used by
DVC to book villas at wdw (in order to get cash by renting through CRO so they could pay the cruise division for the cruise).
Assuming it's true that more resale owners means fewer trades for cruises, that would only help explain why we get fewer questions about "why are villas available on disney.com for cash but I can't book anything on pts."