I think you're conflating the realities of the overall timeshare market, where bargain rentals are frequently found, with
DVC a bit too much. Of course one can stay elsewhere- off property or not even going to WDW, but that isn't the comparison. This is the one timeshare that is on property at WDW and DL, and it trades for a premium for that reason.
Sure, you can find something drastically cheaper in Gatlinburg. But the morning commute from there to rope drop at Epcot is pretty painful. And yes, there are dirt cheap lodgings in Kissimmee and Orlando as well. If a given person is content with those, then it would be unreasonable for them to own or rent DVC. But that doesn't stop hundreds of thousands of other people from doing so.
My point is, if you think you're going to be able to frequently get into VGF, BCV, or other high demand bookings using distressed last-minute-before-expiration points, you're just not correct. All available rooms at those places will have been taken months previous, outside of the random stray single night, or fleeting availability on a cancellation. And I don't know of any DVC renters (or brokers) that will offer a waitlist and stalk the website for a prospective renter. They will offer what is available right now, and tell you what isn't.
If you don't think many people are rushing to book certain DVC properties and times of year at $16+ a point, check over the next year and see for yourself how often you are able to rent a points stay at VGF for $12.
Your point about value versus moderate versus deluxe for a price-sensitive buyer is true, but just because one buyer will be content substituting Coronado Springs for the Grand Floridian, does not mean that other buyers would make the same decision.