Disney does not particularly care about this.
Though I would definitley agree that if the resale market collapses, there is no resale market.
I like the MouseSavers one. The assumptions they use are overly-favorable to buying vs. renting (they have the purchase price at $210 and rental rates at $23) but the underlying spreadsheet can be modified to something more reasonable.
https://www.mousesavers.com/other-disney-vacations/disney-vacation-club/#opportunity
So if I ran that correctly, assuming I bought 160 Riviera points today (enough points for a week's stay during the summer in a preferred view studio, nothing ostentatious) - versus renting at $20 a point, I wouldn't come out ahead with my purchase until 2066, and the resort expires in 2070.
Care to comment @tjkraz ?