Do they do that?? That would be terrible to spend that much, and then have it not be enough.
They can only reallocate points. They can't add points to the system without building new villas/rooms.
Basically, the total number of points to book rooms at any particular resort can't change, but they can make changes to what the different bookings cost.
For example,
DVC finds that december is a popular time of year, so they might raise the number of points in december, but in doing so they have to lower the cost of another time of year. Studios might be more popular, so they'll raise the cost of a studio but lower the cost of a one and/or two bedroom.
The reason they do this is to keep the system balanced. In a perfect world, all rooms should be booked 100% (with the exception of maintenance and refurbs). but, if everybody wants to book christmas, they have to make that time less desirable by making it more expensive, which would encourage people to book other times of year.
That being said, they've only ever given the
point charts a major overhaul once. And that was for 2010. They increased the points of the more popular times, but lowered the points of less popular times.
Real example: Many members only do a sun-thursday night booking because the points for those nights are much cheaper than fri-sat nights. This created an imbalance and they corrected it with the 2010 charts by lowering the weekend cost a little bit and raising the weeknight cost a little bit. In most cases, the number of points for any given full week didn't change except by maybe a point or two.
This sun-thur point increase caused a lot of the people who only travel sun-thur to not have enough points for their usual trip. But for people like me who tend to go for long weekends (4-5 nights) it actually helped out just a little bit.
All that being said, dramatic
point chart changes are EXTREMELY rare for DVC. Buy maybe 5-10 points more than you calculate you'll need and every few years you can go for an extra day, or upgrade to a bigger room. If/when they make a change to the point chart, you'll have a few points buffer. But if you buy exactly the number of points you'll need, and they change it so your week costs one more point than it used to (this actually happened), then you're hosed.