I've been to Disney 15 or so times. I've taken the DVC tour a couple of times. Here are my reasons why I haven't joined.
1.I think it's irresponsible. There are too many variables in life that occur. I could lose my job tomorrow and what if I can't sell it right away? Credit goes bye-bye really fast.
2.I don't like the accomodations. I think the studio rooms at the locations I've seen aren't as nice as the regular hotel rooms.
3.I like having housekeeping everyday and not having to pay extra for it.
4.The cost of the points once you buy may not increase, but the number of points it takes to stay year to year does. It's the same difference.
5.I've always been perfectly content staying at a Value Resort.
6.If you look hard enough, you can stay cheaper in a moderate and still not spend much more than you would with DVC.
Bottom line is, last time I got back, I sat down for a long time and looked at the cost. I wrote it down in every way imaginable, with different point purchases, cost increases, time we stay, etc. I don't care what anyone says, unless you're paying cash up front for it, you're not saving as much as they want you to believe. If you pay cash up front, don't count yearly dues, and only stay in Deluxe accomodations, sure - It can save you money. The more variables you take out of that equation, the less money you save.
A few points:
1) Pay cash or finance very short term. I know, lots of people can't do that and, rightly so, that may make DVC "not right" for them. I wouldn't say DVC is irresponsible to purchase...rather there are irresponsible WAYS to purchase it.
2) I think thats a matter of personal taste. Most of the studios I've seen (SSR, BCV, and the AKV models) are as nice as any hotel room I've seen on property...again, a matter of personal taste.
3) A valid point. I don't mind only getting trash and towel, and having to purchase an additional towel pack on check in. As for other "cleaning"...I don't make the bed every day at home...it doesn't bother me not to have it made on vacation.

I LIKE the idea of having a laundry facility free for use, and in room for a 1BR or larger, because it means we have to pack less. That's worth running the machine
4) NOT true. Absolutely, 100%, not true. The total number of points at a resort can NEVER, EVER change. If one week goes up, another has to come down (Easter is a good example of this) to balance it out. If one accomodation type goes up, another has to come down. There will ALWAYS be the same "number" of points at a resort, every year.
5) Then DVC is not for you.
6)True, right now. Moderate hotel rates seem to be very close to the break even point, and with discounts...they're lower. Today. 15 years from now, if you were to buy into DVC today? Probably not, when looking at historical information, and comparing room rate increases to dues increases.
Cash up front, with dues, at AKV your ppt cost is about 6.53 per point (the most expensive option, I think, right now). For one week, in a standard studio at AKV (83 points) in value season, that comes out to 541.99, or 77.42 per night. You get almost 2 full weeks (6 points short) in value season for that 160 point minimum. If you travel during peak season, (Xmas and Easter...144 pts per week), that goes up to 940.32, or 134.33 per night.
Financing would about double that cost, I think.
On "opportunity cost", assuming a 7% APY, you'd need to spend right around 1200 for accomondations for DVC to be "worth" it over investing the same 160 point "cost" and adding to it with dues money.
I, too, have run these numbers 6 different ways from Sunday, and, for OUR vacation habits, and OUR situation, I can't make them NOT be a good deal. I'm sure others (like you) with different habits or situations might see differently. But as I've said in another thread: For us, it's a good deal. To determine if it is for YOU, you really have to put the numbers through the paces that make sense for you, and your family.