I'm a stockholder and DVC member, but how do you "plan to benefit"? There are no stockholder perks in the parks, no pass discounts, no "advantages" whatsoever. It is simply an investment, and should be viewed as a long-term investment, since the cash dividends are nothing to brag about.
As far as "why no discount on passes" for DVC members...there is a 10% on UHP passes, but many DVCers choose not to buy them and opt for either the PHs that do not expire, or an AP if we will be at WDW more than 8 days per year. Unless WDW sees 1) a sales advantage or 2) a major drop in DVCers going to the parks, there is no financial reason that justifies offering discounts on park passes. And didn't most of us buy into DVC because we would be going to the parks, so I don't see that major park attendance drop off happening. What does happen (at least for us) is we spend fewer hours in the parks each day and enjoy a more relaxed touring style, thus making APs perfect in our case.