It goes to show how little I know. I just assumed that the mandatory resorts were setup for trading within network whether it was from the developer or resale. I am puzzled to why Starwood would setup Mandatory and Voluntary if both have the same functions if bought from the developer.
Add resorts can trade within the network when purchased from the developer. If purchased resale, only mandatory resorts have Staroptions.
The initial differentiation (mandatory resorts) between developer and resale was no ability to convert to hotel Starpoints (like Marriott). As hotel points got devalued, and the option to convert to hotel points became less attractive, I assume they decided at some point they need to do more. I presume they thought that if the product on the resale market was significantly less attractive then people would necessarily have to buy retail. If they could turn the mandatory resorts to voluntary they would do it in a heartbeat.
The problem for Starwood, the way I see it, is that people will buy developer if (i) the differential between resale and retail prices justifies what you get extra (e.g. Staroptions, Starpoints, or Elite status), or (ii) if the buyer is unaware of the resale market. The "benefit" of SVN was sold so much that it, along with high MFs, killed the resale values of voluntary resorts. So if people know about the resale market, why pay $55K for an annual WPORV when you can buy it for less than 10% that amount on the resale market. And if you want Staroptions to trade, WKV and SVV are mostly the things people look at on the resale market. That leaves selling only to people who haven't learned about the resale market or to the very few who know of and can afford the Elite program. Given that it's relatively easy to find TUG during the allotted time to rescind, it's getting harder and harder to sell...
Raising MFs and killing the resale value more, will only make things worse. IMO, the only thing that can save SVN in the long run is reigning in MFs to make ownership attractive again, and allowing all resale units into SVN, both of which will increase resale prices and reduce the differential between resale and retail. The less attractive alternative (for them) is to lower retail prices...