The issue with all of the suggestions is they come from different divisions. So
DVC does have to pay for those things. They can't just offer theme park passes for free and not have it be a line item on the DVC P&L, because parks aren't going to write off that on THEIR P&L from the goodness of their hearts. Similar with
DDP (which is through resorts - "free dining" is actually paid for via the resorts and is part of THEIR P&L, which is why inventory is so strict and limited).
Like any big company, the different groups run in parallel, and one group can't just borrow a benefit from another without there being some form of payment. For stuff like DDP or parks passes, it ends up being a fairly expensive proposition without a lot of qualification.
Something like a one-time park pass (with new purchase) is much more feasible than ongoing, because it can be qualified against purchase size, and it also has a limit and a single line item to be charged against.
This is also why MoonLight Magic events work - they are paying for the park rental and the amenities, but they are limited in scope and duration. Both the parks and DVC have clear accounting for the expense and income.