Gross oversimplification alert!!!
In a "traditional" timeshare, one purchases a fixed week and has access to the unit for that single week per year. When the resort is sold out, every unit is occupied 52 weeks per year.
Even though
DVC is point-based, the same concept applies. The point tables are determined ahead of time, and Disney can sell enough points such that every unit would be occupied 365 days / year. As DebbieB indicated, they could "shuffle the deck", making one day more points, but there would have to be an offsetting adjustment elsewhere to reduce the points for another day. The resort, as a whole, must always remain in equilibrium.
That said, DVC members can also use points for things like non-DVC resorts and Disney Cruises. The point requirements for these trades can and DO change annually. Many think the trading values are already outrageous, and I can only imagine what they will look like in 10 or 20 years. Buy DVC to stay at DVC.