So many assumptions in this. Sandi covered most of what I was going to say but I'll add that the biggest assumption is that there's going to be some giant amount of resale owners. I believe most of the data I've seen on the boards points to just 10-20% of all points since the beginning, being resale - that's what, 30 years of DVC and only 20% max has been resold. It will be a very long time before RIV resales cause any issues with RCI and it may never happen - if the bottom falls out of the Riviera resale price, DVC will just take them back at ROFR and make them full benefit points again.
Also, I remember years ago trying to book a Dis resort with a friends RCI points. It was impossible to find anything during most of the year. Things may have changed now but we never bothered looking again after that annoying experience.