Did you mean non-essential? If so, then the answer is all of my non-essential purchases are made with money that could have otherwise been invested. That's obvious. But thanks for misunderstanding my point, and then calling it dumb.
My question was specifically around recouping the initial cost of the DVC purchase via the savings they get through the program, and how folks were figuring that out. In my calculations, I created a vacationing profile - 1 week/year, summer season, moderate lodging - and projected out the cost over the next 20 years (based on historical rack rate % increases over the past 10 years). Then I found a DVC resale that I'd consider (and would give me the minimum points needed to meet the vacationing profile above), and calculated what the maintenance cost would be over the next 20 years (again, based on historical maintenance fee increases). Calculating the total amount of money spent over time on both DVC and non DVC, the vacationing profile I posited (and, is realistic for me) wouldn't ever recoup costs. Eventually, around year 18, DVC would be cheaper annually, but the principal was never recouped. I was skeptical about another poster's claims of recouping their principal, so I asked some clarifying questions to see if I was measuring it in the same way.
I played with my calculations some more, and if I bump the "today" cost of my normal nightly lodging to $300, the situation changes drastically. The money looks like it's fully recouped (even against conservative interest earned otherwise) by year 7. Further, by year 20, the money saved in this new situation is more than the original principal plus interest over that 20 years.
If it's not clear, I have no stance on DVC one way or the other, other than wanting to buy in from an emotional standpoint. Personally, it has to make financial sense, and that's what I'm trying to figure out. Also, I don't buy your stance that because something (financial analysis of future vacation spending) doesn't make sense in extreme, it doesn't make sense in moderation. That's ridiculous. Most things in life make sense in moderation, but not extremes.