I understand what you are saying, I just think it is small minded thinking from Disney.
The biggest competition in the travel industry is every other destination in the world where my family could be spending money, not resale. If I hold my Aulani contract until expiration in 39 years then I will have spent $204k in dues (+inflation) and countless tens of thousands more dollars more on food and merchandise at the hotel. If I use the points to stay near a theme park, that could easily be nearly another $100k in tickets and food/merch over the next 39 years.
That money could be going somewhere else. Don’t they want to create as many “raving fans” as possible that will come back year after year and entice others to think about doing the same?
Yes and no.
"Raving fans" don't tend to spend at the same rate as infrequent guests. Bob Chapek drove this point home more aggressively than others, but it's always been the case. To use your numbers, yes you may spend $100k in food and merchandise over the next 39 years. However, if Disney can instead lure 39 separate families to visit 1x per year, collectively they will spend a lot more than $100k. A LOT more. That's why Disney still has 25,000 hotel rooms rather than converting them all to villas and lowering prices to make DVC affordable to more.
Disney Parks and resorts aren't a resource with unlimited supply. To some extent, Disney chooses to cull the crowds in the interest of finding a balance between price and experience. (Heck, if they were just worried about getting bodies thru the gate, they could cut ticket prices in half immediately. But we both know it's more complicated than that.)
In the end, what they do is a choreographed process of juggling infrequent guests, locals, DVC owners and other groups to find a reasonable mix.
Once DVC points are sold, SOMEONE is going to use them. You can choose to use your points at Aulani, Bay Lake Tower, Hilton Head or any other location. Or you can rent them. Or you can sell them. SOMEONE will use those points. But without a steady stream of new sales, there's no reason for DVC to exist...at least, not the marketing component. Without future sales, there are no new resorts and no member perks. (Perks aren't some generous "thank you gift to our best customers!", they're incentives to buy and keep DVC points.)
Today there are still timeshares sold "new" for thousands of dollars which immediately lose the vast majority of their value. This is a policy that DVC could alter at any time if it backfires. But history suggests most people don't give any consideration to future resale value before buying direct. As such, whatever perks or benefits Disney can add to the list of reasons to buy from them stand to boost the product.