In a pool of hundreds of thousands of members, demand is elastic. The inelastic demands of individual members are mitigated in the aggregate.
Ironically, the "teacher times" are not the times when there are demand problems. DVC members are, broadly speaking, cheapskates, so any rooms that are seen as a bargain or "too good" of a value are the first to go. Generally speaking, there should be less of a gap between room types. Make the expensive times cheaper, and the cheap times more expensive. In an effort to discount the slow periods to combat low demand, Disney has gone too far and actually turned those periods into the highest demand.
The teacher times were my personal example, not that of the general DVC ownership.
While looking at the pool in aggregate it does seem elastic, I wonder how many members as an individual are inelastic. Remember, we are booking reservations on an individual level. I'm sure there are a good number of people who can shift vacation times. But there are also a good number that cannot make big shifts. Kids and school, permitted work vacations, syncing vacations with spouses, etc. That is part of what was a 'qualifier' for DVC, if you can plan your vacation 11 or 7 months out. People who can do that tend to have less flexible vacation schedules.
While you may be able to shift some demand from one period to an other using points, I believe there is a large portion of the population that cannot make that shift.
Now, when you are talking about room sizes and point differences, that is a different story. There are many people out there who budgeted for a studio in their contracts. With studio and 1BR usually sleeping the same number of people, many people went for the studio. I think a lot of sales were also made with the point that you could afford a studio with a small points contract.
I myself prefer a 1BR, even if it just my wife and myself. If we go as a family we get a 2BR. I think the last time we had a studio was because it was all I could get. I would love to see 1BR come down in points, but then availability would tank as well.
I recall there being some sort of rule about shifting points between units as well. I don't think that it was it could not be done, but something about a limit. I'll have to see if I can find it.