Many great points already mentioned.
I, like most here, spent a long time "running the numbers" before taking the plunge. And here is what stops people (many of my friends are in this boat).
Let's take a 200-point contract, which is quite modest by
DVC-standards. Thw initial payment on that contract would be at least 16,000, looking at some avg. resale prices. Now, just put that aside for a sec.
The MFs on that contract are going to run approx. $800/year (and will of course increase...but let's just look at the current year). Remembering that DVC only covers the cost of your lodging...that $800 can easily buy you one week onsite at a variety of resorts (using Disney promotions, discount codes, etc.). So, for the same $800, you can get your Disney lodging, without having to pay out the whopping 16K. When you look at it this way, DVC does not make sense to the average on-looker.
(NOTE: Yes, I know I did not factor in the inflation rates, the fact that resort rates will also increase, etc....but I don't think the type of person the OP is talking about does either...they are just looking at the "top level" information.)
Now, the big difference comes in, of course, when you start talking about the type of room. The 200-point DVC owners can have a 1-BR Villa, while those just paying the $800 for a week onsite will likely end up at POR (which is a lovely resort--not bashing at all). And for many people, this is a-wash. "Sure, it's a bigger space and having your own w/d is a bonus...but I can buy a lot of washers and dryers for 16,000....". OR "Well, yes, the extra space would be great, but we spend all day in the parks anyway, so the resort room is not that important...just as long as we are on site..." And you have heard all of the other arguements.
BUT, this is what tipped the scales for me and DH. Part of our criteria for travelling anywhere for any length of time (even just a quick week-end trip close to home) is that we have a suite...we must have a separate "living room" type of space so that we can put the kids down to bed and he and I can stay up and have some adult time. So, we DVC is definitely for us.
And for me personally, I loved the idea of a pre-paid vacation. Yup, the initial price tag is hard for everyone to swallow, but I knew that it would guarantee us a vacation every year--something we dearly need with the amount we work and the age of our children. So, I was happy to pre-pay for many years worth of vacations, as I knew that would be the only way we would take vacations regularly.