The difficulty with calling it a Ponzi scheme is that the apparent desire is to call the retail TS purchasers investors in the scheme with their desired returns being supported by proceeds from future sales. It’s never really been set up that way. There have been representations that a TS ownership is real estate that will appreciate in value over time rather than experience the rapid depreciation on the resale market. That can be a completely different issue.
TS developers have never to my knowledge taken the proceeds from sales to distribute to early customers. Those proceeds go to commissions, marketing expenses , and corporate profits instead. Some customers do benefit from the use of some proceeds as marketing expenses in the form of benefits to regular customers, but it would be a stretch to characterize this state as making it a Ponzi, particularly since those regular customers pay higher annual dues.
If you want to call it fraud, call it fraud. That’s a more apt characterization, though the developers do quite a bit to insulate themselves from actual fraud in written disclosures that often go unread. You could say it operates similar to a Ponzi for some aspects, but it strikes me as needing to exaggerate those similarities beyond reasonable limits to get a likeness. Bottom line for me is that on the sales side, the developers go a fair way to say they are selling vacations rather than investments. On the investment side, they distribute proceeds of vacation sales as dividends and other than the initial IPO or additional capital raising stock issuances they don’t really take money from investors. I don’t see how anyone skilled in the art of investment would call it a Ponzi.